diff --git a/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini b/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini
index 76b44d9e9cf..3605e8f3fc9 100644
--- a/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/FileAPI/url/url-in-tags-revoke.window.js.ini
@@ -4,7 +4,7 @@
     expected: TIMEOUT
 
   [Opening a blob URL in a new window immediately before revoking it works.]
-    expected: FAIL
+    expected: TIMEOUT
 
   [Fetching a blob URL immediately before revoking it works in an iframe.]
     expected: FAIL
diff --git a/tests/wpt/metadata-layout-2020/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini b/tests/wpt/metadata-layout-2020/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini
index 0d1aec4f066..51400f93eac 100644
--- a/tests/wpt/metadata-layout-2020/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini
+++ b/tests/wpt/metadata-layout-2020/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini
@@ -14,6 +14,9 @@
   [Object.prototype.toString applied after nulling the prototype]
     expected: FAIL
 
+  [Object.prototype.toString applied to a null-prototype instance]
+    expected: FAIL
+
 
 [class-string-iterator-prototype-object.any.worker.html]
   [Object.prototype.toString]
@@ -31,3 +34,6 @@
   [Object.prototype.toString applied after nulling the prototype]
     expected: FAIL
 
+  [Object.prototype.toString applied to a null-prototype instance]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini
similarity index 67%
rename from tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
rename to tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini
index 4bfb0c2053a..f29da48a2a0 100644
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini
@@ -1,4 +1,4 @@
-[hit-test-floats-004.html]
+[hit-test-floats-003.html]
   [Miss float below something else]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini
deleted file mode 100644
index baa9f1a7541..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-005.html]
-  [Miss clipped float]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini b/tests/wpt/metadata-layout-2020/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini
index 5496474410b..a647125277a 100644
--- a/tests/wpt/metadata-layout-2020/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini
@@ -1,2 +1,2 @@
 [mix-blend-mode-animation.html]
-  expected: FAIL
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata-layout-2020/css/css-text-decor/text-decoration-thickness-valid.html.ini b/tests/wpt/metadata-layout-2020/css/css-text-decor/text-decoration-thickness-valid.html.ini
index e89dadce620..4531d44c22d 100644
--- a/tests/wpt/metadata-layout-2020/css/css-text-decor/text-decoration-thickness-valid.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/css-text-decor/text-decoration-thickness-valid.html.ini
@@ -23,3 +23,15 @@
   [e.style['text-decoration-thickness'\] = "-10px" should set the property value]
     expected: FAIL
 
+  [e.style['text-decoration-thickness'\] = "calc(100% - 40em)" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-thickness'\] = "10%" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-thickness'\] = "-27%" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-thickness'\] = "calc(40% - 20px)" should set the property value]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini b/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini
index 4a1e8110f6f..f8e7e539aae 100644
--- a/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/css-transforms/transform-scale-hittest.html.ini
@@ -2,3 +2,6 @@
   [Hit test intersecting scaled box]
     expected: FAIL
 
+  [Hit test within unscaled box]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/css-transitions/Document-getAnimations.tentative.html.ini b/tests/wpt/metadata-layout-2020/css/css-transitions/Document-getAnimations.tentative.html.ini
new file mode 100644
index 00000000000..d94c5e25011
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/css-transitions/Document-getAnimations.tentative.html.ini
@@ -0,0 +1,22 @@
+[Document-getAnimations.tentative.html]
+  [CSS Transitions targetting (pseudo-)elements should have correct order after sorting]
+    expected: FAIL
+
+  [getAnimations for CSS Transitions]
+    expected: FAIL
+
+  [Transitions are not returned after they have finished]
+    expected: FAIL
+
+  [CSS Transitions targetting (pseudo-)elements should have correct order after sorting (::marker)]
+    expected: FAIL
+
+  [getAnimations for non-animated content]
+    expected: FAIL
+
+  [getAnimations for CSS Transitions sort by property name]
+    expected: FAIL
+
+  [getAnimations for CSS Transitions sort by transition generation]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/css-variables/css-variable-change-style-001.html.ini b/tests/wpt/metadata-layout-2020/css/css-variables/css-variable-change-style-001.html.ini
new file mode 100644
index 00000000000..443089ea5e2
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/css-variables/css-variable-change-style-001.html.ini
@@ -0,0 +1,28 @@
+[css-variable-change-style-001.html]
+  [Test changing 'color' value to become a css variable]
+    expected: FAIL
+
+  [Test declaration changes on 'color' as variable]
+    expected: FAIL
+
+  [Avoid masking differences on 'color' due to declaration changes]
+    expected: FAIL
+
+  [Test declaration changes on 'white-space' as variable]
+    expected: FAIL
+
+  [Test declaration changes on 'background-color' as variable]
+    expected: FAIL
+
+  [Test changing 'white-space' value to become a css variable]
+    expected: FAIL
+
+  [Test changing 'background-color' value to become a css variable]
+    expected: FAIL
+
+  [Avoid masking differences on 'background-color' due to declaration changes]
+    expected: FAIL
+
+  [Avoid masking differences on 'white-space' due to declaration changes]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/css-variables/css-variable-change-style-002.html.ini b/tests/wpt/metadata-layout-2020/css/css-variables/css-variable-change-style-002.html.ini
new file mode 100644
index 00000000000..5781474a926
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/css-variables/css-variable-change-style-002.html.ini
@@ -0,0 +1,10 @@
+[css-variable-change-style-002.html]
+  [Declaration changes on 'color' propagate to all variable references]
+    expected: FAIL
+
+  [Declaration changes on 'background-color' propagate to all variable references]
+    expected: FAIL
+
+  [Declaration changes on 'white-space' propagate to all variable references]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
index c3e80f60581..a6c39d50087 100644
--- a/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
@@ -8,6 +8,3 @@
   [throws if handleEvent is thruthy and not callable]
     expected: FAIL
 
-  [looks up handleEvent method on every event dispatch]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
index 9418ebdeaea..45789ac5aae 100644
--- a/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
@@ -318,24 +318,21 @@
   [<iframe>: separate response Content-Type: text/html */*]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html;" \\" text/plain]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: */* text/html]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html;" text/plain]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html;" text/plain]
-    expected: FAIL
-
   [<iframe>: combined response Content-Type: text/html */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*]
+  [<iframe>: combined response Content-Type: text/html;charset=gbk text/plain text/html]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/html;x=" text/plain]
+  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;" \\" text/plain]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini
index d2df9b78483..258fe374697 100644
--- a/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/fetch/content-type/script.window.js.ini
@@ -56,3 +56,6 @@
   [separate text/javascript x/x]
     expected: FAIL
 
+  [separate text/javascript ]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini
index 333df26fe72..61682d248e2 100644
--- a/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,9 +11,6 @@
   [X-Content-Type-Options%3A%20nosniff%2C%2C%40%23%24%23%25%25%26%5E%26%5E*()()11!]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20no%0D%0AX-Content-Type-Options%3A%20nosniff]
-    expected: FAIL
-
-  [Content-Type-Options%3A%20nosniff]
+  [X-Content-Type-Options%3A%20%40%23%24%23%25%25%26%5E%26%5E*()()11!%2Cnosniff]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
new file mode 100644
index 00000000000..87b07c3e670
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
@@ -0,0 +1,4 @@
+[traverse_the_history_1.html]
+  [Multiple history traversals from the same task]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
similarity index 71%
rename from tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
rename to tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
index 385376c7321..dc2e45516de 100644
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
@@ -1,4 +1,4 @@
-[traverse_the_history_4.html]
+[traverse_the_history_5.html]
   [Multiple history traversals, last would be aborted]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html.ini b/tests/wpt/metadata-layout-2020/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html.ini
new file mode 100644
index 00000000000..0fade722cfa
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html.ini
@@ -0,0 +1,2 @@
+[drawImage-with-src-rect.tentative.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata-layout-2020/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini b/tests/wpt/metadata-layout-2020/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini
index f45aaafe1c5..af14e19a466 100644
--- a/tests/wpt/metadata-layout-2020/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini
@@ -1,16 +1,20 @@
 [supported-elements.html]
+  expected: TIMEOUT
   [Contenteditable element should support autofocus]
     expected: FAIL
 
   [Host element with delegatesFocus including no focusable descendants should be skipped]
-    expected: FAIL
+    expected: NOTRUN
 
   [Element with tabindex should support autofocus]
-    expected: FAIL
+    expected: TIMEOUT
 
   [Area element should support autofocus]
-    expected: FAIL
+    expected: NOTRUN
 
   [Host element with delegatesFocus should support autofocus]
-    expected: FAIL
+    expected: NOTRUN
+
+  [Non-HTMLElement should not support autofocus]
+    expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
index e63fe7c263e..4df5d7a35de 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
@@ -1,5 +1,4 @@
 [iframe_sandbox_popups_escaping-2.html]
-  expected: CRASH
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
-    expected: TIMEOUT
+    expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
index 338d283eb0e..93673c2a0db 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
@@ -1,4 +1,5 @@
 [iframe_sandbox_popups_escaping-3.html]
+  expected: CRASH
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index d913fcbb129..3080be9afc0 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
@@ -1,5 +1,5 @@
 [iframe_sandbox_popups_nonescaping-1.html]
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
index 0407f0cc2b7..9eb581fcf1f 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
@@ -1,5 +1,5 @@
 [iframe_sandbox_popups_nonescaping-2.html]
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
index f4f994c5d6f..7a36937927c 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
@@ -1,5 +1,4 @@
 [iframe_sandbox_popups_nonescaping-3.html]
-  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
-    expected: NOTRUN
+    expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-img-element/image-compositing-change.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-img-element/image-compositing-change.html.ini
new file mode 100644
index 00000000000..e3b35a275da
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-img-element/image-compositing-change.html.ini
@@ -0,0 +1,2 @@
+[image-compositing-change.html]
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/forms/form-submission-0/historical.window.js.ini b/tests/wpt/metadata-layout-2020/html/semantics/forms/form-submission-0/historical.window.js.ini
new file mode 100644
index 00000000000..d61d941a4ac
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/semantics/forms/form-submission-0/historical.window.js.ini
@@ -0,0 +1,4 @@
+[historical.window.html]
+  [invalid event is only supported for form controls]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html.ini b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html.ini
new file mode 100644
index 00000000000..83d23da3b74
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html.ini
@@ -0,0 +1,34 @@
+[k-rate-dynamics-compressor-connections.html]
+  [X release: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [X attack: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [Executing "release"]
+    expected: FAIL
+
+  [X ratio: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [Executing "threshold"]
+    expected: FAIL
+
+  [# AUDIT TASK RUNNER FINISHED: 5 out of 5 tasks were failed.]
+    expected: FAIL
+
+  [Executing "ratio"]
+    expected: FAIL
+
+  [Executing "knee"]
+    expected: FAIL
+
+  [Executing "attack"]
+    expected: FAIL
+
+  [X knee: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [X threshold: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/workers/shared-worker-in-data-url-context.window.js.ini b/tests/wpt/metadata-layout-2020/workers/shared-worker-in-data-url-context.window.js.ini
index 10dda3a6659..daa7a8c41bc 100644
--- a/tests/wpt/metadata-layout-2020/workers/shared-worker-in-data-url-context.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/workers/shared-worker-in-data-url-context.window.js.ini
@@ -1,7 +1,8 @@
 [shared-worker-in-data-url-context.window.html]
+  expected: TIMEOUT
   [Create a shared worker in a data url frame]
     expected: FAIL
 
   [Create a data url shared worker in a data url frame]
-    expected: FAIL
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini b/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
index d4f62ed7113..faa00f45ecf 100644
--- a/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
+++ b/tests/wpt/metadata/FileAPI/url/url-in-tags-revoke.window.js.ini
@@ -7,7 +7,7 @@
     expected: FAIL
 
   [Opening a blob URL in a new window immediately before revoking it works.]
-    expected: FAIL
+    expected: TIMEOUT
 
   [Opening a blob URL in a noopener about:blank window immediately before revoking it works.]
     expected: TIMEOUT
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 41e55d31367..fd7e25ae49b 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -10250,6 +10250,20 @@
      ]
     },
     "css-pseudo": {
+     "grammar-error-002-manual.html": [
+      "3cec3df0adb41f5a7345458dee3090175f85f285",
+      [
+       null,
+       {}
+      ]
+     ],
+     "grammar-error-003-manual.html": [
+      "876a7d5565dc08740bc63964828964136ab8bc62",
+      [
+       null,
+       {}
+      ]
+     ],
      "selection-text-shadow-006-manual.html": [
       "57c9ad67d17bd7a3a37acd86bef43989c45d9480",
       [
@@ -158838,6 +158852,45 @@
        {}
       ]
      ],
+     "cascade-highlight-001.html": [
+      "b7d294c6b9762a09f32baae84d4d1665178b667a",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/cascade-highlight-001-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "cascade-highlight-002.html": [
+      "cf13f1c533c36e71ef68077746030fb9c611a1dd",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/cascade-highlight-001-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "cascade-highlight-004.html": [
+      "d1b614fe949530f58a4786871027822f416abd5e",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/cascade-highlight-004-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "first-letter-001.html": [
       "afe1f9b60391b5fb8ca0b222345b869c899208a1",
       [
@@ -159176,6 +159229,32 @@
        {}
       ]
      ],
+     "highlight-z-index-001.html": [
+      "f81d25ceb9d2e4199ad80f827bd27b34013701fc",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/highlight-z-index-001-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "highlight-z-index-002.html": [
+      "692984d863232270b31ca38fca8cc16252d196c9",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/highlight-z-index-002-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "marker-and-other-pseudo-elements.html": [
       "f393db58fe8a9acd9e52494c4cea56b18c636535",
       [
@@ -228251,6 +228330,35 @@
           ],
           {}
          ]
+        ],
+        "drawImage-with-src-rect.tentative.html": [
+         "260f96e5cac13e800762ce55db08e36838f85abc",
+         [
+          null,
+          [
+           [
+            "/html/canvas/element/drawing-images-to-the-canvas/image-orientation/reference/drawImage-with-src-rect-ref.html",
+            "=="
+           ]
+          ],
+          {
+           "fuzzy": [
+            [
+             null,
+             [
+              [
+               30,
+               30
+              ],
+              [
+               100,
+               100
+              ]
+             ]
+            ]
+           ]
+          }
+         ]
         ]
        }
       },
@@ -232033,6 +232141,19 @@
          {}
         ]
        ],
+       "image-compositing-change.html": [
+        "592720a82a266c72a507a8651a0dd85ab428663a",
+        [
+         null,
+         [
+          [
+           "/html/semantics/embedded-content/the-img-element/image-compositing-change-ref.html",
+           "=="
+          ]
+         ],
+         {}
+        ]
+       ],
        "image-loading-lazy-slow-aspect-ratio.html": [
         "2d302970cab98fa13cd5653c025003286efb7b29",
         [
@@ -299144,6 +299265,14 @@
       "ae3222595453ec46cf48810cb2f276126897bac6",
       []
      ],
+     "cascade-highlight-001-ref.html": [
+      "aaebc77ca997db470355161f4e4813624e18adcc",
+      []
+     ],
+     "cascade-highlight-004-ref.html": [
+      "7cca053e681993aa71f14738c76d4f66d8e235ad",
+      []
+     ],
      "first-letter-001-ref.html": [
       "f5af1227aa2e90fe0782c320060c5e448a529420",
       []
@@ -299228,6 +299357,14 @@
       "ecdb308f2f426af4f2763fabb30f7244f42fcf62",
       []
      ],
+     "highlight-z-index-001-ref.html": [
+      "0e9f9c252b2244f7ba0a33aaccf9cf0c12420e4c",
+      []
+     ],
+     "highlight-z-index-002-ref.html": [
+      "652c8d9d924402da341a019af190513db21771fd",
+      []
+     ],
      "marker-and-other-pseudo-elements-ref.html": [
       "796acbf75980cd62d30ade419359bda8c666b12e",
       []
@@ -315285,7 +315422,7 @@
       []
      ],
      "testharness-api.md": [
-      "bb855b1723890c809539294159bb815ea1356f25",
+      "8160ca298ed3dcac1fbb2f9c3153e27260d758c1",
       []
      ],
      "testharness-tutorial.md": [
@@ -321437,6 +321574,10 @@
          "drawImage-from-element-swap-width-height-ref.html": [
           "21f0f88b881d748c8a22986caf2f78b770c80c76",
           []
+         ],
+         "drawImage-with-src-rect-ref.html": [
+          "d59dd2d9fd77a83ec02f87edd1aca2b7d1717604",
+          []
          ]
         }
        }
@@ -328592,6 +328733,10 @@
         "2fb0255609adc25a3394ae3edbd75ce4a43cb06d",
         []
        ],
+       "image-compositing-change-ref.html": [
+        "ea80d8b545ff978775ebcff54b3083520bed8334",
+        []
+       ],
        "image-loading-lazy-slow-aspect-ratio-ref.html": [
         "6de01a9b3bbf19567555af2524f8950abdfb2d81",
         []
@@ -328627,6 +328772,10 @@
         ]
        },
        "resources": {
+        "blue-10.png": [
+         "62949e08d87dfcdc0987eaef67692c7a1c16aa50",
+         []
+        ],
         "cat.jpg": [
          "a4f14f54d60e592f3ca8b44360931898602ba6fe",
          []
@@ -332548,6 +332697,10 @@
       "ee7988c551f6429eea2b929af083ad30cbd5c73d",
       []
      ],
+     "test-adapter.js": [
+      "7a3d2c20b831824e609ee4326ef15a93d868b334",
+      []
+     ],
      "util.js": [
       "2ef971ddb79166bbf8c6593c4d57ca3a5feca83b",
       []
@@ -332595,7 +332748,7 @@
     ]
    },
    "lint.ignore": [
-    "5f793cb6f3ec885017eeaf4cd7b4074d93e4d605",
+    "acdeddbff3935e919bc582bdbdb1af1d6693f26d",
     []
    ],
    "loading": {
@@ -334491,13 +334644,33 @@
      "ea3f6b335c7620acf59f546fd48484bf624ccb38",
      []
     ],
+    "parent-yes-child1-no-child2-yes-children-different.sub.https.html.headers": [
+     "ea3f6b335c7620acf59f546fd48484bf624ccb38",
+     []
+    ],
+    "parent-yes-child1-no-child2-yes-children-same.sub.https.html.headers": [
+     "ea3f6b335c7620acf59f546fd48484bf624ccb38",
+     []
+    ],
+    "parent-yes-child1-yes-child2-no-children-same.sub.https.html.headers": [
+     "ea3f6b335c7620acf59f546fd48484bf624ccb38",
+     []
+    ],
+    "parent-yes-child1-yes-child2-yes-children-different.sub.https.html.headers": [
+     "ea3f6b335c7620acf59f546fd48484bf624ccb38",
+     []
+    ],
+    "parent-yes-child1-yes-child2-yes-children-same.sub.https.html.headers": [
+     "ea3f6b335c7620acf59f546fd48484bf624ccb38",
+     []
+    ],
     "resources": {
      "helpers.mjs": [
-      "e088ffb4e9034216c356366fcc25b18cbe60406a",
+      "fcef1b7e74f4d99995405d2602cc5e08a3fbddb6",
       []
      ],
      "send-origin-isolation-header.py": [
-      "8654b087dfa0a859c5f29886e0208eb8f5c4af15",
+      "1a39740f64f83d5e7d7a3f0fc39eb1a01fdc714a",
       []
      ]
     }
@@ -337864,7 +338037,7 @@
      []
     ],
     "testharness.js": [
-     "68d3cc70c465befab5c43c62e0f2d31674129190",
+     "360ed5d845b000deb8e3d58649a188eb9a861731",
      []
     ],
     "testharness.js.headers": [
@@ -348115,7 +348288,7 @@
         []
        ],
        "firefox.py": [
-        "f60185eb25f2e3140562dde5d96624f7081e4571",
+        "09e2764ce37ebf0c3fd5fece2e8ef37f654101fd",
         []
        ],
        "firefox_android.py": [
@@ -348817,6 +348990,10 @@
        "8d0f25058d49205155b84d1619f06a3a7d14cf5a",
        []
       ],
+      "test_request.py": [
+       "869d3d4604409411984cb49fcd40eb7e971b3c52",
+       []
+      ],
       "test_stash.py": [
        "31af1558b0cc5c046843e0e96569db42c467cf22",
        []
@@ -348852,7 +349029,7 @@
        []
       ],
       "request.py": [
-       "a80bc0c8300acfcf766512b89ecfee338bac2295",
+       "89d52a9817edb0f609c3d4c1c9453dde1a149643",
        []
       ],
       "response.py": [
@@ -366432,7 +366609,7 @@
       ]
      ],
      "class-string-iterator-prototype-object.any.js": [
-      "2185ae0bb7bac6aec4d69c9cbf364eb4754427bd",
+      "f878eb7b35b0834accbfd24ddc7d0557334e094f",
       [
        "WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.html",
        {}
@@ -367210,7 +367387,7 @@
      ]
     ],
     "idlharness.https.any.js": [
-     "f9744c8f944fcefe5a6a21e9a7644cf88644c173",
+     "61f517fdc7980a8b1666f6a19003cea4f3a29b34",
      [
       "background-fetch/idlharness.https.any.html",
       {
@@ -367226,8 +367403,13 @@
         [
          "script",
          "/resources/idlharness.js"
+        ],
+        [
+         "timeout",
+         "long"
         ]
-       ]
+       ],
+       "timeout": "long"
       }
      ],
      [
@@ -367245,8 +367427,13 @@
         [
          "script",
          "/resources/idlharness.js"
+        ],
+        [
+         "timeout",
+         "long"
         ]
-       ]
+       ],
+       "timeout": "long"
       }
      ],
      [
@@ -367264,8 +367451,13 @@
         [
          "script",
          "/resources/idlharness.js"
+        ],
+        [
+         "timeout",
+         "long"
         ]
-       ]
+       ],
+       "timeout": "long"
       }
      ],
      [
@@ -367283,8 +367475,13 @@
         [
          "script",
          "/resources/idlharness.js"
+        ],
+        [
+         "timeout",
+         "long"
         ]
-       ]
+       ],
+       "timeout": "long"
       }
      ]
     ],
@@ -368986,7 +369183,7 @@
       ]
      ],
      "idlharness.tentative.https.window.js": [
-      "f4e6d9586966b160811b5da0006a99d9abcb8a9f",
+      "a632060e20aefd43a2c6b976e891062ad0c2f7b5",
       [
        "bluetooth/idl/idlharness.tentative.https.window.html",
        {
@@ -368998,8 +369195,13 @@
          [
           "script",
           "/resources/idlharness.js"
+         ],
+         [
+          "timeout",
+          "long"
          ]
-        ]
+        ],
+        "timeout": "long"
        }
       ]
      ]
@@ -388202,10 +388404,12 @@
     },
     "css-paint-api": {
      "idlharness.html": [
-      "aad04a17cc4c660084fa196cb85da5d88b8560d4",
+      "5532779d29f46de9382bb9340c6c522adfe89e4e",
       [
        null,
-       {}
+       {
+        "timeout": "long"
+       }
       ]
      ]
     },
@@ -388925,6 +389129,13 @@
        {}
       ]
      ],
+     "registered-property-change-style-001.html": [
+      "320b44d82e437218564f544208815048aef5c864",
+      [
+       null,
+       {}
+      ]
+     ],
      "registered-property-computation.html": [
       "f03b257246e520bd93055203a5cb27188babc8ca",
       [
@@ -394593,14 +394804,14 @@
       ]
      ],
      "text-decoration-thickness-invalid.html": [
-      "656fa3bba2aee70381eb1c0e82e963f9f4bea502",
+      "7934862a1760b4b0e966d62174ccf79d045f8991",
       [
        null,
        {}
       ]
      ],
      "text-decoration-thickness-valid.html": [
-      "d05c892674844691ec23bcad1bf4dbd8ab53981c",
+      "aa279bc7e8717cce29a61cf80d967d7ba1936ee2",
       [
        null,
        {}
@@ -395163,7 +395374,7 @@
       ]
      ],
      "Document-getAnimations.tentative.html": [
-      "cd97acfd5ec76c7585d5356c86b3832bb0b7bd37",
+      "a8986d0bdbd35789dc95c090135e19116fd9c45b",
       [
        null,
        {}
@@ -397777,7 +397988,7 @@
         ]
        ],
        "text-decoration-thickness.html": [
-        "903ca8603fb882e19c0ecfc6760a64495e6361dd",
+        "dfd923ae7ba27c38893c50bad5b72e5a927bbefa",
         [
          null,
          {}
@@ -398898,6 +399109,20 @@
      ]
     },
     "css-variables": {
+     "css-variable-change-style-001.html": [
+      "798c7727a695c70b8cfcb5588a061de29ef3a3f1",
+      [
+       null,
+       {}
+      ]
+     ],
+     "css-variable-change-style-002.html": [
+      "9057136ddae5640ec2fc13fb3627729f0f7e5c10",
+      [
+       null,
+       {}
+      ]
+     ],
      "test_variable_legal_values.html": [
       "1d86c0834ccb1da7965edf56f9a4aefc0a041421",
       [
@@ -420436,7 +420661,7 @@
      ]
     ],
     "idlharness.window.js": [
-     "33bbe3c14ffe28d961cc4c71c0b367028ff8d2df",
+     "724da3c80179e0aa1cf3875125fd02e2df23905e",
      [
       "feature-policy/idlharness.window.html",
       {
@@ -420448,8 +420673,13 @@
         [
          "script",
          "/resources/idlharness.js"
+        ],
+        [
+         "timeout",
+         "long"
         ]
-       ]
+       ],
+       "timeout": "long"
       }
      ]
     ],
@@ -453536,6 +453766,20 @@
          {}
         ]
        ],
+       "historical.window.js": [
+        "fcc47d90f668437ea072495e8cd41a37c58a1ad7",
+        [
+         "html/semantics/forms/form-submission-0/historical.window.html",
+         {
+          "script_metadata": [
+           [
+            "script",
+            "./resources/targetted-form.js"
+           ]
+          ]
+         }
+        ]
+       ],
        "implicit-submission.optional.html": [
         "109d3b901a53537e9ae2fb17f84d25d4a764b2e2",
         [
@@ -462805,34 +463049,6 @@
        {}
       ]
      ],
-     "precondition-in-promise.html": [
-      "b2a32facad07150258cae3af857c841eb6e2cfae",
-      [
-       null,
-       {}
-      ]
-     ],
-     "precondition-in-setup.html": [
-      "071f140afb6a4b3244dc6793c2ff304d80df4891",
-      [
-       null,
-       {}
-      ]
-     ],
-     "precondition-without-setup.html": [
-      "12188dbdaeb516c8f67cedf78b0989720c81fdac",
-      [
-       null,
-       {}
-      ]
-     ],
-     "precondition.html": [
-      "2e6ddc1d02cc77d4068c1bb2997780f6a03d579d",
-      [
-       null,
-       {}
-      ]
-     ],
      "timeout.html": [
       "29ff348a9af645ff59d860e91af9534e64a606c5",
       [
@@ -464495,7 +464711,7 @@
      ]
     ],
     "simple-block-movement.html": [
-     "0f9257e27ce5d553d8176f084e537e47b331416e",
+     "533f85a68e68949a52772792b915b04696340a4e",
      [
       null,
       {}
@@ -470658,6 +470874,27 @@
       {}
      ]
     ],
+    "parent-no-child1-no-child2-yes-children-different.sub.https.html": [
+     "3c879391a4571398a4254a15906411d5e844c596",
+     [
+      null,
+      {}
+     ]
+    ],
+    "parent-no-child1-no-child2-yes-children-same.sub.https.html": [
+     "5d9161a852f71695922b49015257846150b6408b",
+     [
+      null,
+      {}
+     ]
+    ],
+    "parent-no-child1-yes-child2-no-children-same.sub.https.html": [
+     "d289c8821aebf767c485967b5455b1e5badb3f1a",
+     [
+      null,
+      {}
+     ]
+    ],
     "parent-yes-child-no-same.sub.https.html": [
      "a1b9e4e3f5a230e8e49d3552d338d48f029d07cd",
      [
@@ -470685,6 +470922,41 @@
       null,
       {}
      ]
+    ],
+    "parent-yes-child1-no-child2-yes-children-different.sub.https.html": [
+     "6b09b36a586b5cc6c8f306f47afce99709359252",
+     [
+      null,
+      {}
+     ]
+    ],
+    "parent-yes-child1-no-child2-yes-children-same.sub.https.html": [
+     "b3616a604b9c4e1288e1da8ddce3e9b3a224ba6c",
+     [
+      null,
+      {}
+     ]
+    ],
+    "parent-yes-child1-yes-child2-no-children-same.sub.https.html": [
+     "7e351aaf14a008d9788e3fcfd481ca19138be2f0",
+     [
+      null,
+      {}
+     ]
+    ],
+    "parent-yes-child1-yes-child2-yes-children-different.sub.https.html": [
+     "f7c7ea81459999fc05a25f335fdfb409a05e0fa9",
+     [
+      null,
+      {}
+     ]
+    ],
+    "parent-yes-child1-yes-child2-yes-children-same.sub.https.html": [
+     "ca5528e5096081e1789167ca306d1c97d7ae3214",
+     [
+      null,
+      {}
+     ]
     ]
    },
    "origin-policy": {
@@ -489060,7 +489332,7 @@
      ]
     ],
     "slots-imperative-api-slotchange.tentative.html": [
-     "a2f951a9ff60c020cb9e8be1cc7e4069eab75c78",
+     "1f4ef1531a2b678e016b170244ec47422ff49481",
      [
       null,
       {}
@@ -501776,7 +502048,7 @@
      ]
     ],
     "urlsearchparams-constructor.any.js": [
-     "f7989f70ea0071bc7180e0a23f10aef55335734e",
+     "8d855a4fd4d01cb34732a7e3b3ef2da5f639a82b",
      [
       "url/urlsearchparams-constructor.any.html",
       {}
@@ -505180,7 +505452,7 @@
        ]
       ],
       "commitStyles.html": [
-       "19461844b7c68b42d98135eb3c8bdac0814bba60",
+       "f16412fbcf70ba5ef9cb49f8e0647e98de23a596",
        [
         null,
         {}
@@ -507394,6 +507666,13 @@
         {}
        ]
       ],
+      "k-rate-dynamics-compressor-connections.html": [
+       "c1755cd1559474a464024a2b0344c5dd1d95e803",
+       [
+        null,
+        {}
+       ]
+      ],
       "k-rate-gain.html": [
        "887d9f78db8a79b0aae96b9cdf818cde7b33aa6c",
        [
@@ -509779,7 +510058,7 @@
      ]
     ],
     "RTCDataChannel-close.html": [
-     "a417d66d9aaeda3cf551a981aac05a0732d183e2",
+     "b8feea332ad71ff046ceb4b4590ca2becd2919a6",
      [
       null,
       {
diff --git a/tests/wpt/metadata/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini b/tests/wpt/metadata/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini
index 0d1aec4f066..51400f93eac 100644
--- a/tests/wpt/metadata/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini
+++ b/tests/wpt/metadata/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js.ini
@@ -14,6 +14,9 @@
   [Object.prototype.toString applied after nulling the prototype]
     expected: FAIL
 
+  [Object.prototype.toString applied to a null-prototype instance]
+    expected: FAIL
+
 
 [class-string-iterator-prototype-object.any.worker.html]
   [Object.prototype.toString]
@@ -31,3 +34,6 @@
   [Object.prototype.toString applied after nulling the prototype]
     expected: FAIL
 
+  [Object.prototype.toString applied to a null-prototype instance]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini
similarity index 67%
rename from tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
rename to tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini
index 4bfb0c2053a..f29da48a2a0 100644
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
+++ b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini
@@ -1,4 +1,4 @@
-[hit-test-floats-004.html]
+[hit-test-floats-003.html]
   [Miss float below something else]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini
deleted file mode 100644
index baa9f1a7541..00000000000
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-005.html]
-  [Miss clipped float]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini b/tests/wpt/metadata/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini
index 5496474410b..a647125277a 100644
--- a/tests/wpt/metadata/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini
+++ b/tests/wpt/metadata/css/compositing/mix-blend-mode/mix-blend-mode-animation.html.ini
@@ -1,2 +1,2 @@
 [mix-blend-mode-animation.html]
-  expected: FAIL
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata/css/css-text-decor/text-decoration-thickness-valid.html.ini b/tests/wpt/metadata/css/css-text-decor/text-decoration-thickness-valid.html.ini
index e89dadce620..4531d44c22d 100644
--- a/tests/wpt/metadata/css/css-text-decor/text-decoration-thickness-valid.html.ini
+++ b/tests/wpt/metadata/css/css-text-decor/text-decoration-thickness-valid.html.ini
@@ -23,3 +23,15 @@
   [e.style['text-decoration-thickness'\] = "-10px" should set the property value]
     expected: FAIL
 
+  [e.style['text-decoration-thickness'\] = "calc(100% - 40em)" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-thickness'\] = "10%" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-thickness'\] = "-27%" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-thickness'\] = "calc(40% - 20px)" should set the property value]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini b/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini
index 4a1e8110f6f..f8e7e539aae 100644
--- a/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini
+++ b/tests/wpt/metadata/css/css-transforms/transform-scale-hittest.html.ini
@@ -2,3 +2,6 @@
   [Hit test intersecting scaled box]
     expected: FAIL
 
+  [Hit test within unscaled box]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-transitions/Document-getAnimations.tentative.html.ini b/tests/wpt/metadata/css/css-transitions/Document-getAnimations.tentative.html.ini
index d5a4fbdfeb2..43ad8f8f220 100644
--- a/tests/wpt/metadata/css/css-transitions/Document-getAnimations.tentative.html.ini
+++ b/tests/wpt/metadata/css/css-transitions/Document-getAnimations.tentative.html.ini
@@ -14,3 +14,9 @@
   [CSS Transitions targetting (pseudo-)elements should have correct order after sorting (::marker)]
     expected: FAIL
 
+  [getAnimations for CSS Transitions sort by property name]
+    expected: FAIL
+
+  [getAnimations for CSS Transitions sort by transition generation]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-variables/css-variable-change-style-001.html.ini b/tests/wpt/metadata/css/css-variables/css-variable-change-style-001.html.ini
new file mode 100644
index 00000000000..443089ea5e2
--- /dev/null
+++ b/tests/wpt/metadata/css/css-variables/css-variable-change-style-001.html.ini
@@ -0,0 +1,28 @@
+[css-variable-change-style-001.html]
+  [Test changing 'color' value to become a css variable]
+    expected: FAIL
+
+  [Test declaration changes on 'color' as variable]
+    expected: FAIL
+
+  [Avoid masking differences on 'color' due to declaration changes]
+    expected: FAIL
+
+  [Test declaration changes on 'white-space' as variable]
+    expected: FAIL
+
+  [Test declaration changes on 'background-color' as variable]
+    expected: FAIL
+
+  [Test changing 'white-space' value to become a css variable]
+    expected: FAIL
+
+  [Test changing 'background-color' value to become a css variable]
+    expected: FAIL
+
+  [Avoid masking differences on 'background-color' due to declaration changes]
+    expected: FAIL
+
+  [Avoid masking differences on 'white-space' due to declaration changes]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-variables/css-variable-change-style-002.html.ini b/tests/wpt/metadata/css/css-variables/css-variable-change-style-002.html.ini
new file mode 100644
index 00000000000..5781474a926
--- /dev/null
+++ b/tests/wpt/metadata/css/css-variables/css-variable-change-style-002.html.ini
@@ -0,0 +1,10 @@
+[css-variable-change-style-002.html]
+  [Declaration changes on 'color' propagate to all variable references]
+    expected: FAIL
+
+  [Declaration changes on 'background-color' propagate to all variable references]
+    expected: FAIL
+
+  [Declaration changes on 'white-space' propagate to all variable references]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini b/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
index c3e80f60581..a6c39d50087 100644
--- a/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
+++ b/tests/wpt/metadata/css/cssom-view/MediaQueryList-addListener-handleEvent.html.ini
@@ -8,6 +8,3 @@
   [throws if handleEvent is thruthy and not callable]
     expected: FAIL
 
-  [looks up handleEvent method on every event dispatch]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/fetch/content-type/response.window.js.ini b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
index 9c82b862ad7..062e0e25fa8 100644
--- a/tests/wpt/metadata/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
@@ -318,24 +318,21 @@
   [<iframe>: separate response Content-Type: text/html */*]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html;" \\" text/plain]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: */* text/html]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html;" text/plain]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html;" text/plain]
-    expected: FAIL
-
   [<iframe>: combined response Content-Type: text/html */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*]
+  [<iframe>: combined response Content-Type: text/html;charset=gbk text/plain text/html]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/html;x=" text/plain]
+  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;" \\" text/plain]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/fetch/content-type/script.window.js.ini b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
index d2df9b78483..258fe374697 100644
--- a/tests/wpt/metadata/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
@@ -56,3 +56,6 @@
   [separate text/javascript x/x]
     expected: FAIL
 
+  [separate text/javascript ]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
index 333df26fe72..61682d248e2 100644
--- a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,9 +11,6 @@
   [X-Content-Type-Options%3A%20nosniff%2C%2C%40%23%24%23%25%25%26%5E%26%5E*()()11!]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20no%0D%0AX-Content-Type-Options%3A%20nosniff]
-    expected: FAIL
-
-  [Content-Type-Options%3A%20nosniff]
+  [X-Content-Type-Options%3A%20%40%23%24%23%25%25%26%5E%26%5E*()()11!%2Cnosniff]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
new file mode 100644
index 00000000000..87b07c3e670
--- /dev/null
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
@@ -0,0 +1,4 @@
+[traverse_the_history_1.html]
+  [Multiple history traversals from the same task]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
similarity index 71%
rename from tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
rename to tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
index 385376c7321..dc2e45516de 100644
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
@@ -1,4 +1,4 @@
-[traverse_the_history_4.html]
+[traverse_the_history_5.html]
   [Multiple history traversals, last would be aborted]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html.ini b/tests/wpt/metadata/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html.ini
new file mode 100644
index 00000000000..0fade722cfa
--- /dev/null
+++ b/tests/wpt/metadata/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html.ini
@@ -0,0 +1,2 @@
+[drawImage-with-src-rect.tentative.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini b/tests/wpt/metadata/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini
index 6b68e9094e4..8b743f36e1d 100644
--- a/tests/wpt/metadata/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini
+++ b/tests/wpt/metadata/html/interaction/focus/the-autofocus-attribute/supported-elements.html.ini
@@ -1,16 +1,20 @@
 [supported-elements.html]
+  expected: TIMEOUT
   [Contenteditable element should support autofocus]
     expected: FAIL
 
   [Element with tabindex should support autofocus]
-    expected: FAIL
+    expected: TIMEOUT
 
   [Host element with delegatesFocus including no focusable descendants should be skipped]
-    expected: FAIL
+    expected: NOTRUN
 
   [Area element should support autofocus]
-    expected: FAIL
+    expected: NOTRUN
 
   [Host element with delegatesFocus should support autofocus]
-    expected: FAIL
+    expected: NOTRUN
+
+  [Non-HTMLElement should not support autofocus]
+    expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
index e63fe7c263e..4df5d7a35de 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
@@ -1,5 +1,4 @@
 [iframe_sandbox_popups_escaping-2.html]
-  expected: CRASH
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
-    expected: TIMEOUT
+    expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
index f6a7aca3306..cb0211f1d21 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-3.html.ini
@@ -1,5 +1,6 @@
 [iframe_sandbox_popups_escaping-3.html]
   type: testharness
+  expected: CRASH
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index 9df1ac56f2a..963d4cd20ef 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
@@ -1,6 +1,6 @@
 [iframe_sandbox_popups_nonescaping-1.html]
   type: testharness
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
index d43f38b40cd..45d8be1c898 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-2.html.ini
@@ -1,6 +1,6 @@
 [iframe_sandbox_popups_nonescaping-2.html]
   type: testharness
-  expected: TIMEOUT
+  expected: CRASH
   [Check that popups from a sandboxed iframe do not escape the sandbox]
     expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
index e440b1e38c6..dc856a3d5a3 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-3.html.ini
@@ -1,6 +1,5 @@
 [iframe_sandbox_popups_nonescaping-3.html]
   type: testharness
-  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
-    expected: NOTRUN
+    expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/image-compositing-change.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/image-compositing-change.html.ini
new file mode 100644
index 00000000000..e3b35a275da
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/image-compositing-change.html.ini
@@ -0,0 +1,2 @@
+[image-compositing-change.html]
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata/html/semantics/forms/form-submission-0/historical.window.js.ini b/tests/wpt/metadata/html/semantics/forms/form-submission-0/historical.window.js.ini
new file mode 100644
index 00000000000..d61d941a4ac
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/forms/form-submission-0/historical.window.js.ini
@@ -0,0 +1,4 @@
+[historical.window.html]
+  [invalid event is only supported for form controls]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html.ini
new file mode 100644
index 00000000000..83d23da3b74
--- /dev/null
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html.ini
@@ -0,0 +1,34 @@
+[k-rate-dynamics-compressor-connections.html]
+  [X release: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [X attack: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [Executing "release"]
+    expected: FAIL
+
+  [X ratio: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [Executing "threshold"]
+    expected: FAIL
+
+  [# AUDIT TASK RUNNER FINISHED: 5 out of 5 tasks were failed.]
+    expected: FAIL
+
+  [Executing "ratio"]
+    expected: FAIL
+
+  [Executing "knee"]
+    expected: FAIL
+
+  [Executing "attack"]
+    expected: FAIL
+
+  [X knee: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
+  [X threshold: refNode = new DynamicsCompressorNode(context) incorrectly threw ReferenceError: "DynamicsCompressorNode is not defined".]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/workers/shared-worker-in-data-url-context.window.js.ini b/tests/wpt/metadata/workers/shared-worker-in-data-url-context.window.js.ini
index 10dda3a6659..daa7a8c41bc 100644
--- a/tests/wpt/metadata/workers/shared-worker-in-data-url-context.window.js.ini
+++ b/tests/wpt/metadata/workers/shared-worker-in-data-url-context.window.js.ini
@@ -1,7 +1,8 @@
 [shared-worker-in-data-url-context.window.html]
+  expected: TIMEOUT
   [Create a shared worker in a data url frame]
     expected: FAIL
 
   [Create a data url shared worker in a data url frame]
-    expected: FAIL
+    expected: TIMEOUT
 
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index 76fedc21ad0..a362b43889f 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -10988,7 +10988,7 @@
      []
     ],
     "interfaces.js": [
-     "1b841f053a231bf78d29ffe68e59455363c61502",
+     "f62df6b9c75332a2918b18ec70acfc5d7a795ac0",
      []
     ],
     "nested_asap_script.js": [
diff --git a/tests/wpt/mozilla/tests/mozilla/interfaces.js b/tests/wpt/mozilla/tests/mozilla/interfaces.js
index 1b841f053a2..f62df6b9c75 100644
--- a/tests/wpt/mozilla/tests/mozilla/interfaces.js
+++ b/tests/wpt/mozilla/tests/mozilla/interfaces.js
@@ -59,7 +59,7 @@ function test_interfaces(interfaceNamesInGlobalScope) {
     var sources = [
       ecmaGlobals,
       interfaceNamesInGlobalScope,
-      ["AssertionError", "EventWatcher", "PreconditionFailedError"],
+      ["AssertionError", "EventWatcher", "OptionalFeatureUnsupportedError"],
     ];
 
     var interfaceMap = {};
diff --git a/tests/wpt/web-platform-tests/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js b/tests/wpt/web-platform-tests/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js
index 2185ae0bb7b..f878eb7b35b 100644
--- a/tests/wpt/web-platform-tests/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js
+++ b/tests/wpt/web-platform-tests/WebIDL/ecmascript-binding/class-string-iterator-prototype-object.any.js
@@ -31,6 +31,14 @@ test(t => {
 // was no @@toStringTag, it would fall back to a magic class string. This tests that the bug is
 // fixed.
 
+test(() => {
+  const iterator = (new URLSearchParams()).keys();
+  assert_equals(Object.prototype.toString.call(iterator), "[object URLSearchParams Iterator]");
+
+  Object.setPrototypeOf(iterator, null);
+  assert_equals(Object.prototype.toString.call(iterator), "[object Object]");
+}, "Object.prototype.toString applied to a null-prototype instance");
+
 test(t => {
   const proto = Object.getPrototypeOf(iteratorProto);
   t.add_cleanup(() => {
@@ -39,7 +47,7 @@ test(t => {
 
   Object.setPrototypeOf(iteratorProto, null);
 
-  assert_equals(Object.prototype.toString.call(iteratorProto), "[object Object]");
+  assert_equals(Object.prototype.toString.call(iteratorProto), "[object URLSearchParams Iterator]");
 }, "Object.prototype.toString applied after nulling the prototype");
 
 // This test must be last.
diff --git a/tests/wpt/web-platform-tests/background-fetch/idlharness.https.any.js b/tests/wpt/web-platform-tests/background-fetch/idlharness.https.any.js
index f9744c8f944..61f517fdc79 100644
--- a/tests/wpt/web-platform-tests/background-fetch/idlharness.https.any.js
+++ b/tests/wpt/web-platform-tests/background-fetch/idlharness.https.any.js
@@ -1,6 +1,7 @@
 // META: global=window,worker
 // META: script=/resources/WebIDLParser.js
 // META: script=/resources/idlharness.js
+// META: timeout=long
 
 'use strict';
 
diff --git a/tests/wpt/web-platform-tests/bluetooth/idl/idlharness.tentative.https.window.js b/tests/wpt/web-platform-tests/bluetooth/idl/idlharness.tentative.https.window.js
index f4e6d958696..a632060e20a 100644
--- a/tests/wpt/web-platform-tests/bluetooth/idl/idlharness.tentative.https.window.js
+++ b/tests/wpt/web-platform-tests/bluetooth/idl/idlharness.tentative.https.window.js
@@ -1,5 +1,6 @@
 // META: script=/resources/WebIDLParser.js
 // META: script=/resources/idlharness.js
+// META: timeout=long
 
 'use strict';
 
diff --git a/tests/wpt/web-platform-tests/css/css-paint-api/idlharness.html b/tests/wpt/web-platform-tests/css/css-paint-api/idlharness.html
index aad04a17cc4..5532779d29f 100644
--- a/tests/wpt/web-platform-tests/css/css-paint-api/idlharness.html
+++ b/tests/wpt/web-platform-tests/css/css-paint-api/idlharness.html
@@ -1,5 +1,6 @@
 <!doctype html>
 <title>CSS Painting API IDL tests</title>
+<meta name="timeout" content="long">
 <link rel="help" href="https://drafts.css-houdini.org/css-paint-api/">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
diff --git a/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-change-style-001.html b/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-change-style-001.html
new file mode 100644
index 00000000000..320b44d82e4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-properties-values-api/registered-property-change-style-001.html
@@ -0,0 +1,50 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Variables Test: Style changes on registered properties using variables</title>
+<link rel="author" title="Javier Fernandez Garcia-Boente" href="mailto:jfernandez@igalia.com">
+<link rel="help" href="http://www.w3.org/TR/css-variables-1/#using-variables">
+<meta name="assert" content="A change in the custom property declaration must be propagated to all the descendants">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="outer">
+    <div id="inbetween">
+        <div id="inner"></div>
+    </div>
+</div>
+<script>
+    "use strict";
+    test( function () {
+        outer.style.cssText = '';
+        inbetween.style.cssText = '';
+        inner.style.cssText = 'color: var(--color1)';
+        let initialValue = getComputedStyle(inner).getPropertyValue('color');
+        assert_equals(initialValue, "rgb(0, 0, 0)", "Initial value");
+
+        inbetween.style.cssText = 'color: green';
+        let inheritedValue = getComputedStyle(inner).getPropertyValue('color');
+        assert_equals(inheritedValue, "rgb(0, 128, 0)", "Inherited value");
+
+        CSS.registerProperty({name: '--color1', syntax: '<color>', initialValue: 'red', inherits: true});
+        let actualValue = getComputedStyle(inner).getPropertyValue('color');
+        assert_equals(actualValue, "rgb(255, 0, 0)", "Resolved value");
+    }, "New registered property declaration");
+
+    test( function () {
+        outer.style.cssText = '';
+        inbetween.style.cssText = '';
+        inner.style.cssText = 'color: var(--color2)';
+        let initialValue = getComputedStyle(inner).getPropertyValue('color');
+        assert_equals(initialValue, "rgb(0, 0, 0)", "Initial value");
+
+        outer.style.cssText = '--color2: blue';
+        inbetween.style.cssText = 'color: green';
+        let resolvedValue = getComputedStyle(inner).getPropertyValue('color');
+        assert_equals(resolvedValue, "rgb(0, 0, 255)", "Resolved value");
+
+        outer.style.cssText = '';
+        CSS.registerProperty({name: '--color2', syntax: '<color>', initialValue: 'red', inherits: true});
+        let actualValue = getComputedStyle(inner).getPropertyValue('color');
+        assert_equals(actualValue, "rgb(255, 0, 0)", "Resolved value");
+    }, "Registered property overrides a previous declaration ");
+</script>
+
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-001-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-001-ref.html
new file mode 100644
index 00000000000..aaebc77ca99
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-001-ref.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Reftest Reference</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+
+  <style>
+  div
+    {
+      background-color: green;
+      color: yellow;
+      display: inline;
+      font-size: 300%;
+    }
+  </style>
+
+  <p>Test passes if background color of "Text sample" is green and <strong>not red</strong>.
+
+  <div>Text sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-001.html b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-001.html
new file mode 100644
index 00000000000..b7d294c6b97
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-001.html
@@ -0,0 +1,67 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: higher specificity of selectors (Example 11)</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-cascade">
+  <link rel="match" href="cascade-highlight-001-ref.html">
+
+  <!--
+  Example 11 is
+  https://www.w3.org/TR/css-pseudo-4/#example-c35bf49a
+  -->
+
+  <meta content="" name="flags">
+  <meta name="assert" content="This test is an adaptation (or modified version) of Example 11 (#example-c35bf49a). The 'div &gt; span::selection' selector has an higher specificity than the 'span::selection' selector.">
+
+  <style>
+  div
+    {
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      background-color: green;
+      color: yellow;
+    }
+
+  div > span::selection
+  /*
+  count the number of element names and pseudo-elements in the selector (= d)
+  a=0 b=0 c=0 d=3 -> specificity = 0,0,0,3
+  */
+    {
+      background-color: green;
+    }
+
+  span::selection
+  /*
+  count the number of element names and pseudo-elements in the selector (= d)
+  a=0 b=0 c=0 d=2 -> specificity = 0,0,0,2
+  */
+    {
+      background-color: red;
+      color: yellow;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.selectNodeContents(document.getElementById("test"));
+  /* Then we set the range boundaries to the children of div#test */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <p>Test passes if background color of "Text sample" is green and <strong>not red</strong>.
+
+  <div id="test">Text <span>sample</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-002.html b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-002.html
new file mode 100644
index 00000000000..cf13f1c533c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-002.html
@@ -0,0 +1,54 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: tag selector missing (Example 12)</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-cascade">
+  <link rel="match" href="cascade-highlight-001-ref.html">
+
+  <!--
+  Example 12 is
+  https://www.w3.org/TR/css-pseudo-4/#example-97480f68
+  -->
+
+  <meta content="" name="flags">
+  <meta name="assert" content="This test is an adaptation (or modified version) of Example 12 (#example-97480f68). In this test, &ltspan&gt; element's ::selection matches the ::selection { background-color: green; } rule and not the div#test::selection rule because '*' is implied when a tag selector is missing.">
+
+  <style>
+  div
+    {
+      font-size: 300%;
+    }
+
+  ::selection
+    {
+      background-color: green;
+      color: yellow;
+    }
+
+  div#test::selection
+    {
+      background-color: red;
+      color: black;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.selectNodeContents(document.getElementById("test"));
+  /* Then we set the range boundaries to the children of div#test */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <p>Test passes if background color of "Text sample" is green and <strong>not red</strong>.
+
+  <div id="test"><span>Text sample</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-004-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-004-ref.html
new file mode 100644
index 00000000000..7cca053e681
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-004-ref.html
@@ -0,0 +1,21 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Reftest Reference</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+
+  <style>
+  div
+    {
+      background-color: yellow;
+      color: green;
+      display: inline;
+      font-size: 300%;
+    }
+  </style>
+
+   <p>Test passes if "Text sample" is green and if its background color is yellow.
+
+  <div>Text sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-004.html b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-004.html
new file mode 100644
index 00000000000..d1b614fe949
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/cascade-highlight-004.html
@@ -0,0 +1,52 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: inheritance of selection highlight colors from its parent element</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-cascade">
+  <link rel="match" href="cascade-highlight-004-ref.html">
+
+  <meta content="" name="flags">
+  <meta name="assert" content="In this test, 'color' and 'background-color' have not been given a value for the span element. Since its parent element has an highlight pseudo-element, then these values should be inherited. Therefore the span element should be green on a yellow background and should not use the OS default selection highlight color values.">
+
+  <!--
+  When any supported property is not given a value by the
+  cascade, its value is determined by inheritance from the
+  corresponding highlight pseudo-element of its originating
+  element's parent element (regardless of whether that property
+  is an inherited property).
+  https://www.w3.org/TR/css-pseudo-4/#highlight-cascade
+  -->
+
+  <style>
+  div
+    {
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      background-color: yellow;
+      color: green;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.selectNodeContents(document.getElementById("test"));
+  /* Then we set the range boundaries to the children of div#test */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <p>Test passes if "Text sample" is green and if its background color is yellow.
+
+  <div id="test"><span>Text sample</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/grammar-error-002-manual.html b/tests/wpt/web-platform-tests/css/css-pseudo/grammar-error-002-manual.html
new file mode 100644
index 00000000000..3cec3df0adb
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/grammar-error-002-manual.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+
+ <html lang="en">
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: highlighting of grammar error</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-selectors">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-styling">
+
+  <meta content="" name="flags">
+
+  <style>
+  input
+    {
+      font-size: 300%;
+    }
+
+  input::grammar-error
+    {
+      color: maroon;
+      text-decoration: underline dotted red;
+    }
+  </style>
+
+  <p>PREREQUISITE: User agent needs to have an enabled and capable grammar error module. If it does not, then this test does not apply to such user agent.
+
+  <p>Test passes if each glyph of "thing" is maroon and if "thing" is underlined with a red dotted line.
+
+  <div><input type="text" value="Many thing can happen"></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/grammar-error-003-manual.html b/tests/wpt/web-platform-tests/css/css-pseudo/grammar-error-003-manual.html
new file mode 100644
index 00000000000..876a7d5565d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/grammar-error-003-manual.html
@@ -0,0 +1,32 @@
+<!DOCTYPE html>
+
+ <html lang="en">
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: highlighting of grammar error</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-selectors">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-styling">
+
+  <meta content="" name="flags">
+
+  <style>
+  textarea
+    {
+      font-size: 300%;
+    }
+
+  textarea::grammar-error
+    {
+      color: maroon;
+      text-decoration: underline dotted red;
+    }
+  </style>
+
+  <p>PREREQUISITE: User agent needs to have an enabled and capable grammar error module. If it does not, then this test does not apply to such user agent.
+
+  <p>Test passes if each glyph of "thing" is maroon and if "thing" is underlined with a red dotted line.
+
+  <div><textarea cols="20" rows="2">Many thing can happen</textarea></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-001-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-001-ref.html
new file mode 100644
index 00000000000..0e9f9c252b2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-001-ref.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Reftest Reference</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+
+  <style>
+  div
+    {
+      background-color: yellow;
+      color: green;
+      display: inline-block;
+      font-size: 48px;
+      line-height: 1.25; /* computes to 60px */
+      position: relative;
+      top: 1.25em;
+    }
+  </style>
+
+  <p>Test passes if "Text sample" is green and if its background color is yellow.
+
+  <div>Test sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-001.html b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-001.html
new file mode 100644
index 00000000000..f81d25ceb9d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-001.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: highlight pseudo-element drawn below positioned element</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-painting">
+  <link rel="match" href="highlight-z-index-001-ref.html">
+
+  <meta content="" name="flags">
+  <meta name="assert" content="This test checks that the ::selection pseudo-element must be drawn below a relatively positioned element. In this test, such relatively positioned element is a preceding sibling element.">
+
+  <style>
+  div
+    {
+      font-size: 48px;
+      line-height: 1.25; /* computes to 60px */
+    }
+
+  div#rel-positioned-sibling
+    {
+      background-color: yellow;
+      color: green;
+      display: inline-block;
+      position: relative;
+      top: 1.25em;
+    }
+
+  div#test::selection
+    {
+      background-color: red;
+      color: yellow;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.selectNodeContents(document.getElementById("test"));
+  /* Then we set the range boundaries to the children of div#test */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <p>Test passes if "Text sample" is green and if its background color is yellow.
+
+  <div id="rel-positioned-sibling">Test sample</div>
+
+  <div id="test">Test sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-002-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-002-ref.html
new file mode 100644
index 00000000000..652c8d9d924
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-002-ref.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Reftest Reference</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+
+  <style>
+  div
+    {
+      background-color: yellow;
+      color: green;
+      display: inline-block;
+      font-size: 48px;
+      line-height: 1.25; /* computes to 60px */
+    }
+  </style>
+
+  <p>Test passes if "Text sample" is green and if its background color is yellow.
+
+  <div>Test sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-002.html b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-002.html
new file mode 100644
index 00000000000..692984d8632
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/highlight-z-index-002.html
@@ -0,0 +1,53 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: highlight pseudo-element drawn below positioned element</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-painting">
+  <link rel="match" href="highlight-z-index-002-ref.html">
+
+  <meta content="" name="flags">
+  <meta name="assert" content="This test checks that the ::selection pseudo-element must be drawn below an absolutely positioned element. In this test, such absolutely positioned element is a preceding sibling element.">
+
+  <style>
+  div
+    {
+      font-size: 48px;
+      line-height: 1.25; /* computes to 60px */
+    }
+
+  div#abs-positioned-sibling
+    {
+      background-color: yellow;
+      color: green;
+      position: absolute;
+    }
+
+  div#test::selection
+    {
+      background-color: red;
+      color: yellow;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.selectNodeContents(document.getElementById("test"));
+  /* Then we set the range boundaries to the children of div#test */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <p>Test passes if "Text sample" is green and if its background color is yellow.
+
+  <div id="abs-positioned-sibling">Test sample</div>
+
+  <div id="test">Test sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-invalid.html b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-invalid.html
index 656fa3bba2a..7934862a176 100644
--- a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-invalid.html
+++ b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-invalid.html
@@ -18,10 +18,6 @@ test_invalid_value("text-decoration-thickness", "60002020");
 test_invalid_value("text-decoration-thickness", "!@#$%^&");
 test_invalid_value("text-decoration-thickness", "10e2");
 test_invalid_value("text-decoration-thickness", "from font");
-test_invalid_value("text-decoration-thickness", "10%");
-test_invalid_value("text-decoration-thickness", "-27%");
-test_invalid_value("text-decoration-thickness", "calc(40% - 20px)");
-test_invalid_value("text-decoration-thickness", "calc(100% - 40em)");
 </script>
 </body>
 </html>
diff --git a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-valid.html b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-valid.html
index d05c8926748..aa279bc7e87 100644
--- a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-valid.html
+++ b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-thickness-valid.html
@@ -19,6 +19,10 @@ test_valid_value("text-decoration-thickness", "-49em");
 test_valid_value("text-decoration-thickness", "53px");
 test_valid_value("text-decoration-thickness", "calc(40em - 10px)");
 test_valid_value("text-decoration-thickness", "calc(-50em + 13px)");
+test_valid_value("text-decoration-thickness", "10%");
+test_valid_value("text-decoration-thickness", "-27%");
+test_valid_value("text-decoration-thickness", "calc(40% - 20px)");
+test_valid_value("text-decoration-thickness", "calc(100% - 40em)");
 </script>
 </body>
 </html>
diff --git a/tests/wpt/web-platform-tests/css/css-transitions/Document-getAnimations.tentative.html b/tests/wpt/web-platform-tests/css/css-transitions/Document-getAnimations.tentative.html
index cd97acfd5ec..a8986d0bdbd 100644
--- a/tests/wpt/web-platform-tests/css/css-transitions/Document-getAnimations.tentative.html
+++ b/tests/wpt/web-platform-tests/css/css-transitions/Document-getAnimations.tentative.html
@@ -35,6 +35,56 @@ test(t => {
                 'getAnimations returns no running CSS Transitions');
 }, 'getAnimations for CSS Transitions');
 
+test(t => {
+  const div = addDiv(t);
+
+  // Add a couple of transitions
+  div.style.top = '0px';
+  div.style.left = '0px';
+  getComputedStyle(div).transitionProperty;
+
+  div.style.transition = 'all 100s';
+  div.style.top = '100px';
+  div.style.left = '100px';
+
+  var animations = document.getAnimations();
+  assert_equals(animations.length, 2,
+                'getAnimations returns two running CSS Transitions');
+  assert_equals(animations[0].transitionProperty, 'left');
+  assert_equals(animations[1].transitionProperty, 'top');
+}, 'getAnimations for CSS Transitions sort by property name');
+
+promise_test(async t => {
+  const div = addDiv(t);
+
+  // Add a couple of transitions
+  div.style.top = '0px';
+  div.style.left = '0px';
+  getComputedStyle(div).transitionProperty;
+
+  div.style.transition = 'all 100s';
+  div.style.top = '100px';
+  div.style.left = '100px';
+
+  var animations = document.getAnimations();
+  assert_equals(animations.length, 2,
+                'getAnimations returns two running CSS Transitions');
+  assert_equals(animations[0].transitionProperty, 'left');
+  assert_equals(animations[1].transitionProperty, 'top');
+
+  await waitForAnimationFrames(2);
+
+  div.style.opacity = '1'
+  div.style.transition = 'all 100s';
+  div.style.opacity = '0'
+  animations = document.getAnimations();
+  assert_equals(animations.length, 3,
+                'getAnimations returns two running CSS Transitions');
+  assert_equals(animations[0].transitionProperty, 'left', '1');
+  assert_equals(animations[1].transitionProperty, 'top', '2');
+  assert_equals(animations[2].transitionProperty, 'opacity', '3');
+}, 'getAnimations for CSS Transitions sort by transition generation');
+
 function pseudoTest(description, testMarkerPseudos) {
   test(t => {
     // Create two divs with the following arrangement:
diff --git a/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/text-decoration-thickness.html b/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/text-decoration-thickness.html
index 903ca8603fb..dfd923ae7ba 100644
--- a/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/text-decoration-thickness.html
+++ b/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/text-decoration-thickness.html
@@ -17,7 +17,9 @@ runPropertyTests('text-decoration-thickness', [
   { syntax: 'auto' },
   {
     syntax: '<length>',
-    specified: assert_is_equal_with_range_handling
+  },
+  {
+    syntax: '<percentage>',
   },
 ]);
 
diff --git a/tests/wpt/web-platform-tests/css/css-variables/css-variable-change-style-001.html b/tests/wpt/web-platform-tests/css/css-variables/css-variable-change-style-001.html
new file mode 100644
index 00000000000..798c7727a69
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-variables/css-variable-change-style-001.html
@@ -0,0 +1,96 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Variables Test: Style changes on properties using variables</title>
+<link rel="author" title="Javier Fernandez Garcia-Boente" href="mailto:jfernandez@igalia.com">
+<link rel="help" href="http://www.w3.org/TR/css-variables-1/#using-variables">
+<meta name="assert" content="A change in the custom property declaration must be propagated to all the descendants">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+    .inner {
+        color: var(--x);
+        background-color: var(--x);
+        white-space: var(--x);
+    }
+</style>
+<div id="outer">
+    <div id="inbetween">
+        <div id="inner"></div>
+    </div>
+</div>
+<script>
+    "use strict";
+    let colorValues = [
+        { Id: "case1", outer: "red",   inbetween: "",     expected: "rgb(255, 0, 0)" },
+        { Id: "case2", outer: "red",   inbetween: "blue", expected: "rgb(0, 0, 255)" },
+        { Id: "case3", outer: "green", inbetween: "blue", expected: "rgb(0, 0, 255)" },
+        { Id: "case4", outer: "green", inbetween: "",     expected: "rgb(0, 128, 0)" },
+        { Id: "case5", outer: "green", inbetween: "red",  expected: "rgb(255, 0, 0)" },
+        { Id: "case6", outer: ""     , inbetween: "red",  expected: "rgb(255, 0, 0)" },
+        { Id: "case7", outer: "blue" , inbetween: ""   ,  expected: "rgb(0, 0, 255)" },
+    ];
+
+    let whiteSpaceValues = [
+        { Id: "case1", outer: "pre",      inbetween: "",         expected: "pre"      },
+        { Id: "case2", outer: "pre-wrap", inbetween: "",         expected: "pre-wrap" },
+        { Id: "case3", outer: "pre-wrap", inbetween: "nowrap",   expected: "nowrap"   },
+        { Id: "case3", outer: "pre-wrap", inbetween: "",         expected: "pre-wrap" },
+        { Id: "case4", outer: "pre-line", inbetween: "normal",   expected: "normal"   },
+        { Id: "case5", outer: "pre-line", inbetween: "",         expected: "pre-line" },
+        { Id: "case6", outer: "",         inbetween: "pre-wrap", expected: "pre-wrap" },
+        { Id: "case7", outer: "",         inbetween: "",         expected: "normal"   },
+    ];
+
+    let testcases = [
+        { property: "color",            values: colorValues,     },
+        { property: "background-color", values: colorValues,     },
+        { property: "white-space",      values: whiteSpaceValues },
+    ];
+
+    function initializeStyles() {
+        outer.style.cssText = "";
+        inbetween.style.cssText = "";
+        inner.style.cssText = "";
+    }
+
+    testcases.forEach(function (testcase) {
+        test( function () {
+            initializeStyles();
+            inner.style.cssText = testcase.property + ': var(--x)';
+            testcase.values.forEach(function (value) {
+                outer.style.cssText = "--x:" + value.outer;
+                inbetween.style.cssText = "--x:" + value.inbetween;
+                let computedStyle = getComputedStyle(inner);
+                let actualValue = computedStyle.getPropertyValue(testcase.property);
+                assert_equals(actualValue, value.expected, value.Id);
+            });
+        }, "Test declaration changes on '" + testcase.property + "' as variable");
+
+        test( function () {
+            initializeStyles();
+            inbetween.style.cssText = testcase.property + ': inherit';
+            inner.style.cssText = testcase.property + ': inherit';
+            testcase.values.forEach(function (value) {
+                outer.style.cssText = "--x:" + value.outer + "; " + testcase.property + ": " + value.outer;
+                let actualValue = getComputedStyle(inner).getPropertyValue(testcase.property);
+                let expectedValue = getComputedStyle(outer).getPropertyValue(testcase.property);
+                assert_equals(actualValue, expectedValue, value.Id);
+            });
+        }, "Avoid masking differences on '" + testcase.property + "' due to declaration changes");
+
+        test( function () {
+            initializeStyles();
+            inbetween.style.cssText = testcase.property + ': inherit';
+            inner.style.cssText = testcase.property + ': inherit';
+            let value1 = testcase.values[0];
+            let value2 = testcase.values[3];
+            outer.style.cssText = "--x:" + value2.outer + "; " + testcase.property + ": " + value1.outer;
+            let actualValue = getComputedStyle(inner).getPropertyValue(testcase.property);
+            assert_equals(actualValue, value1.expected, value1.Id);
+
+            inner.style.cssText = testcase.property + ': var(--x)';
+            actualValue = getComputedStyle(inner).getPropertyValue(testcase.property);
+            assert_equals(actualValue, value2.expected, value2.Id);
+        }, "Test changing '" + testcase.property + "' value to become a css variable");
+    });
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-variables/css-variable-change-style-002.html b/tests/wpt/web-platform-tests/css/css-variables/css-variable-change-style-002.html
new file mode 100644
index 00000000000..9057136ddae
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-variables/css-variable-change-style-002.html
@@ -0,0 +1,56 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Variables Test: Style changes on properties using variables</title>
+<link rel="author" title="Javier Fernandez Garcia-Boente" href="mailto:jfernandez@igalia.com">
+<link rel="help" href="http://www.w3.org/TR/css-variables-1/#using-variables">
+<meta name="assert" content="A change in the custom property declaration must be propagated to all the descendants">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+    .test1 > div > div { color: var(--x); }
+    .test2 > div > div { background-color: var(--x); }
+    .test3 > div > div { white-space: var(--x); }
+</style>
+<div id="outer">
+    <div>
+        <div id="inner1"></div>
+    </div>
+    <div>
+        <div id="inner2"></div>
+    </div>
+    <div>
+        <div id="inner3"></div>
+    </div>
+</div>
+<script>
+    "use strict";
+
+    let colorValues = [
+        { Id: "case1", value: "red",   expected: "rgb(255, 0, 0)" },
+        { Id: "case2", value: "green", expected: "rgb(0, 128, 0)" },
+    ];
+    let whiteSpaceValues = [
+        { Id: "case1", value: "pre-wrap", expected: "pre-wrap" },
+        { Id: "case2", value: "nowrap",   expected: "nowrap" },
+    ];
+    let testcases = [
+        { property: "color",            className: "test1", values: colorValues, },
+        { property: "background-color", className: "test2", values: colorValues, },
+        { property: "white-space",      className: "test3", values: whiteSpaceValues},
+    ];
+
+    testcases.forEach(function (testcase) {
+        test( function () {
+            outer.className = testcase.className;
+            testcase.values.forEach(function (entry) {
+                document.body.style.cssText = "--x: " + entry.value;
+                let actualValue = getComputedStyle(inner1).getPropertyValue(testcase.property);
+                assert_equals(actualValue, entry.expected, entry.Id + "-1");
+                actualValue = getComputedStyle(inner2).getPropertyValue(testcase.property);
+                assert_equals(actualValue, entry.expected, entry.Id + "-2");
+                actualValue = getComputedStyle(inner3).getPropertyValue(testcase.property);
+                assert_equals(actualValue, entry.expected, entry.Id + "-3");
+            });
+        }, "Declaration changes on '" + testcase.property + "' propagate to all variable references");
+    });
+</script>
diff --git a/tests/wpt/web-platform-tests/docs/writing-tests/testharness-api.md b/tests/wpt/web-platform-tests/docs/writing-tests/testharness-api.md
index bb855b17238..8160ca298ed 100644
--- a/tests/wpt/web-platform-tests/docs/writing-tests/testharness-api.md
+++ b/tests/wpt/web-platform-tests/docs/writing-tests/testharness-api.md
@@ -332,8 +332,8 @@ async_test((t) => {
 
 A failing `assert_implements_optional` call is reported as a status of
 `PRECONDITION_FAILED` for the subtest. This unusual status code is a legacy
-leftover from the deprecated `assert_precondition`; see the [RFC that renamed
-it](https://github.com/web-platform-tests/rfcs/pull/48).
+leftover; see the [RFC that introduced
+`assert_implements_optional`](https://github.com/web-platform-tests/rfcs/pull/48).
 
 `assert_implements_optional` can also be used during test setup. For example:
 
@@ -904,9 +904,6 @@ asserts that one `assert_func(actual, expected_array_N, extra_arg1, ..., extra_a
   allows multiple behaviours. Test authors should not use this method simply to hide
   UA bugs.
 
-### **DEPRECATED** `assert_precondition(condition, description)`
-Use `assert_implements` or `assert_implements_optional` instead.
-
 ## Utility functions ##
 
 ### **DEPRECATED** `on_event(object, event, callback)`
diff --git a/tests/wpt/web-platform-tests/feature-policy/idlharness.window.js b/tests/wpt/web-platform-tests/feature-policy/idlharness.window.js
index 33bbe3c14ff..724da3c8017 100644
--- a/tests/wpt/web-platform-tests/feature-policy/idlharness.window.js
+++ b/tests/wpt/web-platform-tests/feature-policy/idlharness.window.js
@@ -1,5 +1,6 @@
 // META: script=/resources/WebIDLParser.js
 // META: script=/resources/idlharness.js
+// META: timeout=long
 
 "use strict";
 
diff --git a/tests/wpt/web-platform-tests/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html b/tests/wpt/web-platform-tests/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html
new file mode 100644
index 00000000000..260f96e5cac
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/canvas/element/drawing-images-to-the-canvas/image-orientation/drawImage-with-src-rect.tentative.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>drawImage with image orientation: from-image and a sub-image source rect</title>
+<link rel="author" title="Stephen Chenney" href="mailto:schenney@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-images-3/#propdef-image-orientation">
+<link rel="match" href="reference/drawImage-with-src-rect-ref.html">
+<meta name=fuzzy content="30;100">
+  <script>
+    window.onload = () => {
+      const img = document.getElementById('img-element');
+
+      const can = document.getElementById('bitmap-canvas');
+      can.height = img.height;
+      can.width = img.width;
+      can.getContext('2d').drawImage(img, 40, 20, 50, 25, 0, 0, can.width, can.height);
+    };
+  </script>
+</head>
+<body>
+  <img id="img-element" src="../../../css/css-images/image-orientation/support/exif-orientation-3-lr.jpg">
+  <canvas id="bitmap-canvas"></canvas>
+</body>
+</html>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/html/canvas/element/drawing-images-to-the-canvas/image-orientation/reference/drawImage-with-src-rect-ref.html b/tests/wpt/web-platform-tests/html/canvas/element/drawing-images-to-the-canvas/image-orientation/reference/drawImage-with-src-rect-ref.html
new file mode 100644
index 00000000000..d59dd2d9fd7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/canvas/element/drawing-images-to-the-canvas/image-orientation/reference/drawImage-with-src-rect-ref.html
@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>reference for drawImage with image orientation: from-image and a sub-image source rect</title>
+<link rel="author" title="Stephen Chenney" href="mailto:schenney@chromium.org">
+  <script>
+    window.onload = () => {
+      const img = document.getElementById('img-element');
+
+      const can = document.getElementById('bitmap-canvas');
+      can.height = img.height;
+      can.width = img.width;
+      can.getContext('2d').drawImage(img, 40, 20, 50, 25, 0, 0, can.width, can.height);
+    };
+  </script>
+</head>
+<body>
+  <img id="img-element" src="../../../../css/css-images/image-orientation/support/exif-orientation-3-lr-pre-rotated.jpg">
+  <canvas id="bitmap-canvas"></canvas>
+</body>
+</html>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/image-compositing-change-ref.html b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/image-compositing-change-ref.html
new file mode 100644
index 00000000000..ea80d8b545f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/image-compositing-change-ref.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+<style>
+#change {
+  height:75px;
+  width:75px;
+}
+</style>
+<img id="change" src="/images/green-16x16.png"></img>
+<img src="/images/green-16x16.png"></img>
diff --git a/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/image-compositing-change.html b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/image-compositing-change.html
new file mode 100644
index 00000000000..592720a82a2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/image-compositing-change.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+<title>Composited images correctly re-raster when the image and bounds change</title>
+<meta charset="utf-8">
+<link rel="match" href="image-compositing-change-ref.html"/>
+<link rel="help" href="https://html.spec.whatwg.org/multipage/#the-img-element">
+<style>
+#change {
+  will-change:transform;
+  height:426px; width:426px;
+}
+</style>
+<img id="change" src="image.png"></img>
+<img id="original" src="../../../../images/green-16x16.png"></img>
+<script>
+window.onload = () => {
+  requestAnimationFrame(() => {
+    requestAnimationFrame(() => {
+      let image = document.querySelector('#change');
+      image.style.width = image.style.height = "75px";
+      image.src = original.src;
+
+      requestAnimationFrame(() => {
+        document.documentElement.classList.remove("reftest-wait");
+      });
+    });
+  });
+}
+</script>
+
diff --git a/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/resources/blue-10.png b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/resources/blue-10.png
new file mode 100644
index 00000000000..62949e08d87
Binary files /dev/null and b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-img-element/resources/blue-10.png differ
diff --git a/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/historical.window.js b/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/historical.window.js
new file mode 100644
index 00000000000..fcc47d90f66
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/semantics/forms/form-submission-0/historical.window.js
@@ -0,0 +1,19 @@
+// META: script=./resources/targetted-form.js
+
+test(t => {
+  const form = populateForm('<input required><input type=submit>');
+  t.add_cleanup(() => {
+    form.previousElementSibling.remove();
+    form.remove();
+  });
+  const submitter = form.querySelector('input[type=submit]');
+  let invalid = form.querySelector('[required]');
+  let targets = [];
+  const listener = e => targets.push(e.target.localName);
+  form.addEventListener("invalid", t.step_func(listener));
+  form.oninvalid = t.step_func(listener);
+  invalid.addEventListener("invalid", t.step_func(listener));
+  invalid.oninvalid = t.step_func(listener);
+  submitter.click();
+  assert_array_equals(targets, ["input", "input"]);
+}, "invalid event is only supported for form controls");
diff --git a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-in-promise.html b/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-in-promise.html
deleted file mode 100644
index b2a32facad0..00000000000
--- a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-in-promise.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<!DOCTYPE html>
-<meta charset=utf-8>
-<title>Precondition in promise</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script>
-new Promise(() => {
-  assert_precondition(false);
-});
-</script>
diff --git a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-in-setup.html b/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-in-setup.html
deleted file mode 100644
index 071f140afb6..00000000000
--- a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-in-setup.html
+++ /dev/null
@@ -1,10 +0,0 @@
-<!DOCTYPE html>
-<meta charset=utf-8>
-<title>Precondition in setup</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script>
-setup(() => {
-  assert_precondition(false);
-});
-</script>
diff --git a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-without-setup.html b/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-without-setup.html
deleted file mode 100644
index 12188dbdaeb..00000000000
--- a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition-without-setup.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<!DOCTYPE html>
-<meta charset=utf-8>
-<title>Precondition without wrapping setup</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script>
-assert_precondition(false);
-</script>
diff --git a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition.html b/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition.html
deleted file mode 100644
index 2e6ddc1d02c..00000000000
--- a/tests/wpt/web-platform-tests/infrastructure/expected-fail/precondition.html
+++ /dev/null
@@ -1,31 +0,0 @@
-<!DOCTYPE html>
-<meta charset=utf-8>
-<title>Preconditions in tests</title>
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script>
-test(() => {
-  assert_precondition(false, 'precondition 1');
-}, 'test');
-
-async_test((t) => {
-  assert_precondition(false, 'precondition 2');
-  t.done();
-}, 'async_test immediate');
-
-async_test((t) => {
-  t.step_timeout(() => {
-      assert_precondition(false, 'precondition 3');
-      t.done();
-  }, 100);
-}, 'async_test after timeout');
-
-promise_test(async () => {
-  assert_precondition(false, 'precondition 4');
-}, 'promise_test immediate');
-
-promise_test(async () => {
-  await Promise.resolve();
-  assert_precondition(false, 'precondition 5');
-}, 'promise_test after await');
-</script>
diff --git a/tests/wpt/web-platform-tests/layout-instability/resources/test-adapter.js b/tests/wpt/web-platform-tests/layout-instability/resources/test-adapter.js
new file mode 100644
index 00000000000..7a3d2c20b83
--- /dev/null
+++ b/tests/wpt/web-platform-tests/layout-instability/resources/test-adapter.js
@@ -0,0 +1,5 @@
+// Abstracts expectations for reuse in different test frameworks.
+
+cls_expect = (watcher, expectation) => {
+  assert_equals(watcher.score, expectation.score);
+};
diff --git a/tests/wpt/web-platform-tests/layout-instability/simple-block-movement.html b/tests/wpt/web-platform-tests/layout-instability/simple-block-movement.html
index 0f9257e27ce..533f85a68e6 100644
--- a/tests/wpt/web-platform-tests/layout-instability/simple-block-movement.html
+++ b/tests/wpt/web-platform-tests/layout-instability/simple-block-movement.html
@@ -2,13 +2,12 @@
 <title>Layout Instability: simple block movement is detected</title>
 <link rel="help" href="https://wicg.github.io/layout-instability/" />
 <style>
-
-#shifter { position: relative; width: 300px; height: 100px; }
-
+#shifter { position: relative; width: 300px; height: 200px; }
 </style>
 <div id="shifter"></div>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
+<script src="resources/test-adapter.js"></script>
 <script src="resources/util.js"></script>
 <script>
 
@@ -19,15 +18,15 @@ promise_test(async () => {
   await waitForAnimationFrames(2);
 
   // Modify the position of the div.
-  document.querySelector("#shifter").style = "top: 60px";
+  document.querySelector("#shifter").style = "top: 160px";
 
-  // An element of size (300 x 100) has shifted by 60px.
-  const expectedScore = computeExpectedScore(300 * (100 + 60), 60);
+  // An element of size (300 x 200) has shifted by 160px.
+  const expectedScore = computeExpectedScore(300 * (200 + 160), 160);
 
   // Observer fires after the frame is painted.
-  assert_equals(watcher.score, 0);
+  cls_expect(watcher, {score: 0});
   await watcher.promise;
-  assert_equals(watcher.score, expectedScore);
+  cls_expect(watcher, {score: expectedScore});
 }, 'Simple block movement.');
 
 </script>
diff --git a/tests/wpt/web-platform-tests/lint.ignore b/tests/wpt/web-platform-tests/lint.ignore
index 5f793cb6f3e..acdeddbff39 100644
--- a/tests/wpt/web-platform-tests/lint.ignore
+++ b/tests/wpt/web-platform-tests/lint.ignore
@@ -756,10 +756,3 @@ TESTHARNESS-IN-OTHER-TYPE: svg/extensibility/foreignObject/foreign-object-circul
 TESTHARNESS-IN-OTHER-TYPE: svg/extensibility/foreignObject/foreign-object-under-clip-path-crash.html
 TESTHARNESS-IN-OTHER-TYPE: svg/extensibility/foreignObject/foreign-object-under-defs-crash.html
 TESTHARNESS-IN-OTHER-TYPE: svg/svg-in-svg/svg-in-svg-circular-filter-reference-crash.html
-
-# TODO: Temporary inclusions while we deprecate assert_precondition
-# https://github.com/web-platform-tests/wpt/issues/21971
-ASSERT-PRECONDITION: infrastructure/expected-fail/precondition.html
-ASSERT-PRECONDITION: infrastructure/expected-fail/precondition-in-setup.html
-ASSERT-PRECONDITION: infrastructure/expected-fail/precondition-in-promise.html
-ASSERT-PRECONDITION: resources/testharness.js
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html
new file mode 100644
index 00000000000..3c879391a45
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-different.sub.https.html
@@ -0,0 +1,77 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is not isolated, subdomain child 1 is not isolated, different-subdomain child 2 is isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Order of loading should not matter, but we make it sequential to ensure the
+  // tests are deterministic.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}");
+  frameWindow2 = await insertIframe("{{hosts[][www1]}}", "?1");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since everybody is different-origin, everyone's requests/non-requests get
+// respected.
+//
+// So, the parent and child 1 end up in the site-keyed agent cluster, and child
+// 2 ends up in its own origin-keyed agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "Parent to child1: message event must occur");
+
+promise_test(async () => {
+  // Must not throw
+  frameWindow1.document;
+}, "Parent to child1: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "child1 to child2: messageerror event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "SecurityError");
+}, "child1 to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "messageerror");
+}, "child2 to child1: messageerror event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "SecurityError");
+}, "child2 to child1: setting document.domain must not give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html
new file mode 100644
index 00000000000..5d9161a852f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-no-child2-yes-children-same.sub.https.html
@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is not isolated, subdomain child 1 is not isolated, same-subdomain child 2 is isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Must be sequential, not parallel: frameWindow1 must load first.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}");
+  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since they're different-origin, the parent's isolation non-request is
+// respected, as is frameWindow1's non-request. frameWindow2 requests isolation
+// but is ignored, since frameWindow1 is in the same browsing context group.
+//
+// So, everyone ends up in the site-keyed agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "Parent to child1: message event must occur");
+
+promise_test(async () => {
+  // Must not throw
+  frameWindow1.document;
+}, "Parent to child1: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "Parent to child2: message event must occur");
+
+promise_test(async () => {
+  // Must not throw
+  frameWindow2.document;
+}, "Parent to child2: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child1 to child2: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child1 to child2: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child2 to child1: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child2 to child1: setting document.domain must give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html
new file mode 100644
index 00000000000..d289c8821ae
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-no-child1-yes-child2-no-children-same.sub.https.html
@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is not isolated, subdomain child 1 is isolated, same-subdomain child 2 is not isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Must be sequential, not parallel: frameWindow1 must load first.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
+  frameWindow2 = await insertIframe("{{hosts[][www]}}");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since they're different-origin, the parent's isolation non-request is
+// respected, as is frameWindow1's request. frameWindow2's non-request is
+// ignored, since frameWindow1 is in the same browsing context group.
+//
+// So, the parent ends up in the site-keyed agent cluster, and both children end
+// up in an origin-keyed agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child1: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow1.document;
+  });
+}, "Parent to child1: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child1 to child2: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child1 to child2: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child2 to child1: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child2 to child1: setting document.domain must give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html
new file mode 100644
index 00000000000..6b09b36a586
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html
@@ -0,0 +1,79 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is isolated, subdomain child 1 is not isolated, different-subdomain child 2 is isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Order of loading should not matter, but we make it sequential to ensure the
+  // tests are deterministic.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}");
+  frameWindow2 = await insertIframe("{{hosts[][www1]}}", "?1");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since everybody is different-origin, everyone's requests/non-requests get
+// respected.
+//
+// So, the parent ends up in its origin-keyed agent cluster, child 1 ends up in
+// the site-keyed agent cluster, and child 2 ends up in a different origin-keyed
+// agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child1: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow1.document;
+  });
+}, "Parent to child1: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "child1 to child2: messageerror event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "SecurityError");
+}, "child1 to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "messageerror");
+}, "child2 to child1: messageerror event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "SecurityError");
+}, "child2 to child1: setting document.domain must not give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html.headers b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html.headers
new file mode 100644
index 00000000000..ea3f6b335c7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-different.sub.https.html.headers
@@ -0,0 +1 @@
+Origin-Isolation: ?1
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html
new file mode 100644
index 00000000000..b3616a604b9
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html
@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is isolated, subdomain child 1 is not isolated, same-subdomain child 2 is isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Must be sequential, not parallel: frameWindow1 must load first.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}");
+  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since they're different-origin, the parent's isolation request is respected,
+// as is frameWindow1's non-request. frameWindow2 requests isolation but is
+// ignored, since frameWindow1 is in the same browsing context group.
+//
+// So, the parent ends up in the origin-keyed agent cluster, and both children
+// ends up in the site-keyed one.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child1: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow1.document;
+  });
+}, "Parent to child1: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child1 to child2: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child1 to child2: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child2 to child1: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child2 to child1: setting document.domain must give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html.headers b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html.headers
new file mode 100644
index 00000000000..ea3f6b335c7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-no-child2-yes-children-same.sub.https.html.headers
@@ -0,0 +1 @@
+Origin-Isolation: ?1
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html
new file mode 100644
index 00000000000..7e351aaf14a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html
@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is isolated, subdomain child 1 is isolated, same-subdomain child 2 is not isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Must be sequential, not parallel: frameWindow1 must load first.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
+  frameWindow2 = await insertIframe("{{hosts[][www]}}");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since they're different-origin, the parent's isolation request is respected,
+// as is frameWindow1's request. frameWindow2's non-request is ignored, since
+// frameWindow1 is in the same browsing context group.
+//
+// So, the parent ends up in the origin-keyed agent cluster, and both children
+// ends up in a different origin-keyed agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child1: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow1.document;
+  });
+}, "Parent to child1: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child1 to child2: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child1 to child2: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child2 to child1: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child2 to child1: setting document.domain must give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html.headers b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html.headers
new file mode 100644
index 00000000000..ea3f6b335c7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-no-children-same.sub.https.html.headers
@@ -0,0 +1 @@
+Origin-Isolation: ?1
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html
new file mode 100644
index 00000000000..f7c7ea81459
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html
@@ -0,0 +1,79 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is isolated, subdomain child 1 is isolated, different-subdomain child 2 is isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Order of loading should not matter, but we make it sequential to ensure the
+  // tests are deterministic.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
+  frameWindow2 = await insertIframe("{{hosts[][www1]}}", "?1");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since everybody is different-origin, everyone's requests get
+// respected.
+//
+// So, the parent ends up in its origin-keyed agent cluster, child 1 ends up in
+// a second origin-keyed agent cluster, and child 2 ends up in a third
+// origin-keyed agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child1: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow1.document;
+  });
+}, "Parent to child1: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "child1 to child2: messageerror event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "SecurityError");
+}, "child1 to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "messageerror");
+}, "child2 to child1: messageerror event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "SecurityError");
+}, "child2 to child1: setting document.domain must not give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html.headers b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html.headers
new file mode 100644
index 00000000000..ea3f6b335c7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-different.sub.https.html.headers
@@ -0,0 +1 @@
+Origin-Isolation: ?1
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html
new file mode 100644
index 00000000000..ca5528e5096
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html
@@ -0,0 +1,78 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Parent is isolated, subdomain child 1 is isolated, same-subdomain child 2 is not isolated</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="log"></div>
+
+<script type="module">
+import { insertIframe, sendWasmModule, setBothDocumentDomains,
+         sendWasmModuleBetween, accessDocumentBetween } from "./resources/helpers.mjs";
+
+let frameWindow1, frameWindow2;
+promise_setup(async () => {
+  // Must be sequential, not parallel: frameWindow1 must load first.
+  frameWindow1 = await insertIframe("{{hosts[][www]}}", "?1");
+  frameWindow2 = await insertIframe("{{hosts[][www]}}", "?1");
+
+  await setBothDocumentDomains(frameWindow1);
+  await setBothDocumentDomains(frameWindow2);
+});
+
+
+// Since they're different-origin, the parent's isolation request is respected,
+// as is frameWindow1's request. frameWindow2's request is redundant, since
+// frameWindow1 is in the same browsing context group.
+//
+// So, the parent ends up in the origin-keyed agent cluster, and both children
+// ends up in a different origin-keyed agent cluster.
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow1);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child1: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow1.document;
+  });
+}, "Parent to child1: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModule(frameWindow2);
+
+  assert_equals(whatHappened, "messageerror");
+}, "Parent to child2: messageerror event must occur");
+
+promise_test(async () => {
+  assert_throws_dom("SecurityError", DOMException, () => {
+    frameWindow2.document;
+  });
+}, "Parent to child2: setting document.domain must not give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child1 to child2: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow1, 1);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child1 to child2: setting document.domain must give sync access");
+
+promise_test(async () => {
+  const whatHappened = await sendWasmModuleBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "WebAssembly.Module message received");
+}, "child2 to child1: message event must occur");
+
+promise_test(async () => {
+  const whatHappened = await accessDocumentBetween(frameWindow2, 0);
+
+  assert_equals(whatHappened, "accessed document successfully");
+}, "child2 to child1: setting document.domain must give sync access");
+</script>
diff --git a/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html.headers b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html.headers
new file mode 100644
index 00000000000..ea3f6b335c7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/origin-isolation/parent-yes-child1-yes-child2-yes-children-same.sub.https.html.headers
@@ -0,0 +1 @@
+Origin-Isolation: ?1
diff --git a/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs b/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs
index e088ffb4e90..fcef1b7e74f 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs
+++ b/tests/wpt/web-platform-tests/origin-isolation/resources/helpers.mjs
@@ -20,7 +20,17 @@ export function insertIframe(hostname, header) {
 // that sending such a message will result in a message back.
 export async function sendWasmModule(frameWindow) {
   frameWindow.postMessage(await createWasmModule(), "*");
-  return waitForMessage();
+  return waitForMessage(frameWindow);
+}
+
+export async function sendWasmModuleBetween(frameWindow, indexIntoParentFrameOfDestination) {
+  frameWindow.postMessage({ command: "send WASM module", indexIntoParentFrameOfDestination }, "*");
+  return waitForMessage(frameWindow);
+}
+
+export async function accessDocumentBetween(frameWindow, indexIntoParentFrameOfDestination) {
+  frameWindow.postMessage({ command: "access document", indexIntoParentFrameOfDestination }, "*");
+  return waitForMessage(frameWindow);
 }
 
 // This function is coupled to ./send-origin-isolation-header.py, which ensures
@@ -34,13 +44,19 @@ export async function setBothDocumentDomains(frameWindow) {
   document.domain = document.domain;
 
   frameWindow.postMessage({ command: "set document.domain", newDocumentDomain: document.domain }, "*");
-  const whatHappened = await waitForMessage();
+  const whatHappened = await waitForMessage(frameWindow);
   assert_equals(whatHappened, "document.domain is set");
 }
 
-function waitForMessage() {
+function waitForMessage(expectedSource) {
   return new Promise(resolve => {
-    window.addEventListener("message", e => resolve(e.data), { once: true });
+    const handler = e => {
+      if (e.source === expectedSource) {
+        resolve(e.data);
+        window.removeEventListener("message", handler);
+      }
+    };
+    window.addEventListener("message", handler);
   });
 }
 
diff --git a/tests/wpt/web-platform-tests/origin-isolation/resources/send-origin-isolation-header.py b/tests/wpt/web-platform-tests/origin-isolation/resources/send-origin-isolation-header.py
index 8654b087dfa..1a39740f64f 100644
--- a/tests/wpt/web-platform-tests/origin-isolation/resources/send-origin-isolation-header.py
+++ b/tests/wpt/web-platform-tests/origin-isolation/resources/send-origin-isolation-header.py
@@ -17,17 +17,38 @@ def main(request, response):
     <title>Helper page for origin isolation tests</title>
 
     <script type="module">
-    window.onmessage = e => {
+    import { sendWasmModule } from "./helpers.mjs";
+
+    window.onmessage = async (e) => {
+      // These could come from the parent or siblings.
       if (e.data.constructor === WebAssembly.Module) {
-        parent.postMessage("WebAssembly.Module message received", "*");
-      } else if (e.data.command === "set document.domain") {
+        e.source.postMessage("WebAssembly.Module message received", "*");
+      }
+
+      // These only come from the parent.
+      if (e.data.command === "set document.domain") {
         document.domain = e.data.newDocumentDomain;
         parent.postMessage("document.domain is set", "*");
+      } else if (e.data.command === "send WASM module") {
+        const destinationFrameWindow = parent.frames[e.data.indexIntoParentFrameOfDestination];
+        const whatHappened = await sendWasmModule(destinationFrameWindow);
+        parent.postMessage(whatHappened, "*");
+      } else if (e.data.command === "access document") {
+        const destinationFrameWindow = parent.frames[e.data.indexIntoParentFrameOfDestination];
+        try {
+          destinationFrameWindow.document;
+          parent.postMessage("accessed document successfully", "*");
+        } catch (e) {
+          parent.postMessage(e.name, "*");
+        }
       }
+
+      // We could also receive e.data === "WebAssembly.Module message received",
+      // but that's handled by await sendWasmModule() above.
     };
 
-    window.onmessageerror = () => {
-      parent.postMessage("messageerror", "*");
+    window.onmessageerror = e => {
+      e.source.postMessage("messageerror", "*");
     };
     </script>
     """
diff --git a/tests/wpt/web-platform-tests/resources/testharness.js b/tests/wpt/web-platform-tests/resources/testharness.js
index 68d3cc70c46..360ed5d845b 100644
--- a/tests/wpt/web-platform-tests/resources/testharness.js
+++ b/tests/wpt/web-platform-tests/resources/testharness.js
@@ -1867,24 +1867,11 @@ policies and contribution forms [3].
      */
     function assert_implements_optional(condition, description) {
         if (!condition) {
-            // Due to the difficulty of changing logging statuses, we re-use
-            // the PRECONDITION_FAILED status for assert_implements_optional.
-            // See the RFC: https://github.com/web-platform-tests/rfcs/pull/48
-            //
-            // TODO(smcgruer): Once assert_precondition is removed, rename the
-            // exception and move this comment to where PRECONDITION_FAILED is used.
-            throw new PreconditionFailedError(description);
+            throw new OptionalFeatureUnsupportedError(description);
         }
     }
     expose(assert_implements_optional, "assert_implements_optional")
 
-    function assert_precondition(precondition, description) {
-        if (!precondition) {
-            throw new PreconditionFailedError(description);
-        }
-    }
-    expose(assert_precondition, "assert_precondition");
-
     function Test(name, properties)
     {
         if (tests.file_is_test && tests.tests.length) {
@@ -1990,7 +1977,7 @@ policies and contribution forms [3].
             if (this.phase >= this.phases.HAS_RESULT) {
                 return;
             }
-            var status = e instanceof PreconditionFailedError ? this.PRECONDITION_FAILED : this.FAIL;
+            var status = e instanceof OptionalFeatureUnsupportedError ? this.PRECONDITION_FAILED : this.FAIL;
             var message = String((typeof e === "object" && e !== null) ? e.message : e);
             var stack = e.stack ? e.stack : null;
 
@@ -2576,7 +2563,7 @@ policies and contribution forms [3].
             try {
                 func();
             } catch (e) {
-                this.status.status = e instanceof PreconditionFailedError ? this.status.PRECONDITION_FAILED : this.status.ERROR;
+                this.status.status = e instanceof OptionalFeatureUnsupportedError ? this.status.PRECONDITION_FAILED : this.status.ERROR;
                 this.status.message = String(e);
                 this.status.stack = e.stack ? e.stack : null;
                 this.complete();
@@ -3118,14 +3105,14 @@ policies and contribution forms [3].
         status_text_harness[harness_status.OK] = "OK";
         status_text_harness[harness_status.ERROR] = "Error";
         status_text_harness[harness_status.TIMEOUT] = "Timeout";
-        status_text_harness[harness_status.PRECONDITION_FAILED] = "Precondition Failed";
+        status_text_harness[harness_status.PRECONDITION_FAILED] = "Optional Feature Unsupported";
 
         var status_text = {};
         status_text[Test.prototype.PASS] = "Pass";
         status_text[Test.prototype.FAIL] = "Fail";
         status_text[Test.prototype.TIMEOUT] = "Timeout";
         status_text[Test.prototype.NOTRUN] = "Not Run";
-        status_text[Test.prototype.PRECONDITION_FAILED] = "Precondition Failed";
+        status_text[Test.prototype.PRECONDITION_FAILED] = "Optional Feature Unsupported";
 
         var status_number = {};
         forEach(tests,
@@ -3507,12 +3494,12 @@ policies and contribution forms [3].
         return lines.slice(i).join("\n");
     }
 
-    function PreconditionFailedError(message)
+    function OptionalFeatureUnsupportedError(message)
     {
         AssertionError.call(this, message);
     }
-    PreconditionFailedError.prototype = Object.create(AssertionError.prototype);
-    expose(PreconditionFailedError, "PreconditionFailedError");
+    OptionalFeatureUnsupportedError.prototype = Object.create(AssertionError.prototype);
+    expose(OptionalFeatureUnsupportedError, "OptionalFeatureUnsupportedError");
 
     function make_message(function_name, description, error, substitutions)
     {
@@ -3742,17 +3729,17 @@ policies and contribution forms [3].
 
     if (global_scope.addEventListener) {
         var error_handler = function(error, message, stack) {
-            var precondition_failed = error instanceof PreconditionFailedError;
+            var optional_unsupported = error instanceof OptionalFeatureUnsupportedError;
             if (tests.file_is_test) {
                 var test = tests.tests[0];
                 if (test.phase >= test.phases.HAS_RESULT) {
                     return;
                 }
-                var status = precondition_failed ? test.PRECONDITION_FAILED : test.FAIL;
+                var status = optional_unsupported ? test.PRECONDITION_FAILED : test.FAIL;
                 test.set_status(status, message, stack);
                 test.phase = test.phases.HAS_RESULT;
             } else if (!tests.allow_uncaught_exception) {
-                var status = precondition_failed ? tests.status.PRECONDITION_FAILED : tests.status.ERROR;
+                var status = optional_unsupported ? tests.status.PRECONDITION_FAILED : tests.status.ERROR;
                 tests.status.status = status;
                 tests.status.message = message;
                 tests.status.stack = stack;
@@ -3868,11 +3855,11 @@ tr.notrun > td:first-child {\
     color:blue;\
 }\
 \
-tr.preconditionfailed > td:first-child {\
+tr.optionalunsupported > td:first-child {\
     color:blue;\
 }\
 \
-.pass > td:first-child, .fail > td:first-child, .timeout > td:first-child, .notrun > td:first-child, .preconditionfailed > td:first-child {\
+.pass > td:first-child, .fail > td:first-child, .timeout > td:first-child, .notrun > td:first-child, .optionalunsupported > td:first-child {\
     font-variant:small-caps;\
 }\
 \
diff --git a/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-api-slotchange.tentative.html b/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-api-slotchange.tentative.html
index a2f951a9ff6..1f4ef1531a2 100644
--- a/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-api-slotchange.tentative.html
+++ b/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-api-slotchange.tentative.html
@@ -9,8 +9,9 @@
 <div id="test_slotchange">
   <div id="host">
     <template id="shadow_root" data-mode="open" data-slot-assignment="manual">
-      <slot id="s1"></slot>
+      <slot id="s1"><div id="fb">fallback</div></slot>
       <slot id="s2"></slot>
+      <slot id="s3"></slot>
     </template>
     <div id="c1"></div>
     <div id="c2"></div>
@@ -23,13 +24,15 @@ function getDataCollection() {
   return {
     s1EventCount: 0,
     s2EventCount: 0,
+    s3EventCount: 0,
     s1ResolveFn: null,
-    s2ResolveFn: null
+    s2ResolveFn: null,
+    s3ResolveFn: null,
   }
 }
 
-function setupShadowDOM(test, data) {
-  let tTree = createTestTree(test_slotchange);
+function setupShadowDOM(id, test, data) {
+  let tTree = createTestTree(id);
   tTree.s1.addEventListener('slotchange', (event) => {
     if (!event.isFakeEvent) {
       test.step(function () {
@@ -52,6 +55,17 @@ function setupShadowDOM(test, data) {
     }
     data.s2ResolveFn();
   });
+  tTree.s3.addEventListener('slotchange', (event) => {
+    if (!event.isFakeEvent) {
+      test.step(function () {
+        assert_equals(event.type, 'slotchange', 'slotchange event\'s type must be "slotchange"');
+        // listen to bubbling events.
+        assert_equals(event.relatedTarget, undefined, 'slotchange must not set relatedTarget');
+      });
+      data.s3EventCount++;
+    }
+    data.s3ResolveFn();
+  });
   return tTree;
 }
 
@@ -62,7 +76,10 @@ function monitorSlots(data) {
     const s2Promise = new Promise((resolve, reject) => {
       data.s2ResolveFn = resolve;
     });
-    return [s1Promise, s2Promise];
+    const s3Promise = new Promise((resolve, reject) => {
+      data.s3ResolveFn = resolve;
+    });
+    return [s1Promise, s2Promise, s3Promise];
 }
 </script>
 
@@ -70,7 +87,7 @@ function monitorSlots(data) {
 // Tests:
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange, test, data);
   let [s1Promise, s2Promise] = monitorSlots(data);
 
   tTree.s1.assign([tTree.c1]);
@@ -87,7 +104,7 @@ async_test((test) => {
 
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange, test, data);
   let [s1Promise, s2Promise] = monitorSlots(data);
 
   assert_throws_dom('NotAllowedError', () => { tTree.s1.assign([tTree.c4]); });
@@ -108,7 +125,7 @@ async_test((test) => {
 
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange,test, data);
   let [s1Promise] = monitorSlots(data);
 
   tTree.s1.assign([tTree.c1, tTree.c2]);
@@ -133,7 +150,7 @@ async_test((test) => {
 
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange, test, data);
   let [s1Promise, s2Promise] = monitorSlots(data);
 
   tTree.s1.assign([tTree.c1]);
@@ -147,7 +164,7 @@ async_test((test) => {
 
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange, test, data);
   let [s1Promise, s2Promise] = monitorSlots(data);
 
   tTree.s1.assign([tTree.c1]);
@@ -167,7 +184,7 @@ async_test((test) => {
 
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange, test, data);
   let [s1Promise] = monitorSlots(data);
 
   tTree.s1.assign([tTree.c1]);
@@ -186,7 +203,7 @@ async_test((test) => {
 
 async_test((test) => {
   const data = getDataCollection();
-  let tTree = setupShadowDOM(test, data);
+  let tTree = setupShadowDOM(test_slotchange, test, data);
   let [s1Promise] = monitorSlots(data);
 
   tTree.s1.assign([tTree.c1, tTree.c2]);
@@ -202,4 +219,155 @@ async_test((test) => {
     }));
   }));
 }, "Fire slotchange event when order of assigned nodes changes.");
+
+promise_test((test) => {
+  const data = getDataCollection();
+  let tTree = setupShadowDOM(test_slotchange, test, data);
+  let [s1Promise] = monitorSlots(data);
+
+  assert_array_equals(tTree.s1.assignedNodes({ flatten: true }), [tTree.fb]);
+  let div = document.createElement("div");
+  tTree.s1.appendChild(div);
+
+  return s1Promise.then(test.step_func(() => {
+    assert_equals(data.s1EventCount, 1);
+    assert_array_equals(tTree.s1.assignedNodes({ flatten: true }), [tTree.fb, div]);
+  }));
+}, "Fire slotchange event when slot's fallback content changes.");
+
+promise_test((test) => {
+  const data = getDataCollection();
+  let tTree = setupShadowDOM(test_slotchange, test, data);
+  let [s1Promise] = monitorSlots(data);
+
+  tTree.s1.assign([tTree.c1]);
+
+  return s1Promise.then(test.step_func(() => {
+    assert_equals(data.s1EventCount, 1);
+
+    [s1Promise] = monitorSlots(data);
+    tTree.c1.remove();
+
+    return s1Promise;
+  }))
+  .then(test.step_func(() => {
+      assert_equals(data.s1EventCount, 2);
+  }));
+}, "Fire slotchange event when assigned node is removed.");
+
+promise_test((test) => {
+  const data = getDataCollection();
+  let tTree = setupShadowDOM(test_slotchange, test, data);
+  [s1Promise] = monitorSlots(data);
+
+  tTree.s1.assign([tTree.c1]);
+
+  return s1Promise.then(test.step_func(() => {
+    assert_equals(data.s1EventCount, 1);
+
+    [s1Promise] = monitorSlots(data);
+    tTree.s1.remove();
+
+    return s1Promise;
+  }))
+  .then(test.step_func(() => {
+      assert_equals(data.s1EventCount, 2);
+  }));
+}, "Fire slotchange event when removing a slot from Shadows Root that changes its assigned nodes.");
+
+async_test((test) => {
+  const data = getDataCollection();
+  let tTree = setupShadowDOM(test_slotchange, test, data);
+  let [s1Promise] = monitorSlots(data);
+
+  tTree.s1.remove();
+
+  let fakeEvent = new Event('slotchange');
+  fakeEvent.isFakeEvent = true;
+  tTree.s1.dispatchEvent(fakeEvent);
+
+  s1Promise.then(test.step_func(() => {
+    assert_equals(data.s2EventCount, 0);
+
+    [s1Promise, s2Promise] = monitorSlots(data);
+    tTree.shadow_root.insertBefore(tTree.s1, tTree.s2);
+
+    tTree.s1.dispatchEvent(fakeEvent);
+    tTree.s2.dispatchEvent(fakeEvent);
+
+    Promise.all([s1Promise, s2Promise]).then(test.step_func_done(() => {
+      assert_equals(data.s1EventCount, 0);
+      assert_equals(data.s2EventCount, 0);
+    }));
+  }));
+
+}, "No slotchange event when adding or removing an empty slot.");
+
+async_test((test) => {
+  const data = getDataCollection();
+  let tTree = setupShadowDOM(test_slotchange, test, data);
+  let [s1Promise, s2Promise] = monitorSlots(data);
+
+  tTree.host.appendChild(document.createElement("div"));
+
+  let fakeEvent = new Event('slotchange');
+  fakeEvent.isFakeEvent = true;
+  tTree.s1.dispatchEvent(fakeEvent);
+  tTree.s2.dispatchEvent(fakeEvent);
+
+  Promise.all([s1Promise, s2Promise]).then(test.step_func(() => {
+    assert_equals(data.s1EventCount, 0);
+    assert_equals(data.s2EventCount, 0);
+
+    [s1Promise, s2Promise] = monitorSlots(data);
+    tTree.shadow_root.insertBefore(document.createElement("div"), tTree.s2);
+
+    tTree.s1.dispatchEvent(fakeEvent);
+    tTree.s2.dispatchEvent(fakeEvent);
+
+    Promise.all([s1Promise, s2Promise]).then(test.step_func_done(() => {
+      assert_equals(data.s1EventCount, 0);
+      assert_equals(data.s2EventCount, 0);
+    }));
+  }));
+
+}, "No slotchange event when adding another slotable.");
+
+</script>
+
+<div id="test_nested_slotchange">
+  <div>
+    <template data-mode="open" data-slot-assignment="manual">
+      <div>
+        <template data-mode="open" data-slot-assignment="manual">
+          <slot id="s2"></slot>
+          <slot id="s3"></slot>
+        </template>
+        <slot id="s1"></slot>
+      </div>
+    </template>
+    <div id="c1"></div>
+  </div>
+</div>
+
+<script>
+async_test((test) => {
+  const data = getDataCollection();
+  let tTree = setupShadowDOM(test_nested_slotchange, test, data);
+  let [s1Promise, s2Promise, s3Promise] = monitorSlots(data);
+
+  tTree.s3.assign([tTree.s1]);
+
+  s3Promise.then(test.step_func(() => {
+    assert_equals(data.s3EventCount, 1);
+    [s1Promise, s2Promise, s3Promise] = monitorSlots(data);
+
+    tTree.s1.assign([tTree.c1]);
+
+    Promise.all([s1Promise, s3Promise]).then(test.step_func_done(() => {
+      assert_equals(data.s1EventCount, 1);
+      assert_equals(data.s3EventCount, 2);
+    }));
+  }));
+}, "Fire slotchange event when assign node to nested slot, ensure event bubbles ups.");
 </script>
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py
index f60185eb25f..09e2764ce37 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py
@@ -488,7 +488,7 @@ class OutputHandler(object):
 
     def __call__(self, line):
         """Write a line of output from the firefox process to the log"""
-        if "GLib-GObject-CRITICAL" in line:
+        if b"GLib-GObject-CRITICAL" in line:
             return
         if line:
             if not self.setup_ran:
diff --git a/tests/wpt/web-platform-tests/tools/wptserve/tests/test_request.py b/tests/wpt/web-platform-tests/tools/wptserve/tests/test_request.py
new file mode 100644
index 00000000000..869d3d46044
--- /dev/null
+++ b/tests/wpt/web-platform-tests/tools/wptserve/tests/test_request.py
@@ -0,0 +1,78 @@
+import mock
+from six import binary_type
+
+from wptserve.request import Request, RequestHeaders
+
+
+class MockHTTPMessage(dict):
+    """A minimum (and not completely correctly) mock of HTTPMessage for testing.
+
+    Constructing HTTPMessage is annoying and different in Python 2 and 3. This
+    only implements the parts used by RequestHeaders.
+
+    Requirements for construction:
+    * Keys are header names and MUST be lower-case.
+    * Values are lists of header values (even if there's only one).
+    * Keys and values should be native strings to match stdlib's behaviours.
+    """
+    def __getitem__(self, key):
+        assert isinstance(key, str)
+        values = dict.__getitem__(self, key.lower())
+        assert isinstance(values, list)
+        return values[0]
+
+    def get(self, key, default=None):
+        try:
+            return self[key]
+        except KeyError:
+            return default
+
+    def getallmatchingheaders(self, key):
+        values = dict.__getitem__(self, key.lower())
+        return ["{}: {}\n".format(key, v) for v in values]
+
+
+def test_request_headers_get():
+    raw_headers = MockHTTPMessage({
+        'x-foo': ['foo'],
+        'x-bar': ['bar1', 'bar2'],
+    })
+    headers = RequestHeaders(raw_headers)
+    assert headers['x-foo'] == b'foo'
+    assert headers['X-Bar'] == b'bar1, bar2'
+    assert headers.get('x-bar') == b'bar1, bar2'
+
+
+def test_request_headers_encoding():
+    raw_headers = MockHTTPMessage({
+        'x-foo': ['foo'],
+        'x-bar': ['bar1', 'bar2'],
+    })
+    headers = RequestHeaders(raw_headers)
+    assert isinstance(headers['x-foo'], binary_type)
+    assert isinstance(headers['x-bar'], binary_type)
+    assert isinstance(headers.get_list('x-bar')[0], binary_type)
+
+
+def test_request_url_from_server_address():
+    request_handler = mock.Mock()
+    request_handler.server.scheme = 'http'
+    request_handler.server.server_address = ('localhost', '8000')
+    request_handler.path = '/demo'
+    request_handler.headers = MockHTTPMessage()
+
+    request = Request(request_handler)
+    assert request.url == 'http://localhost:8000/demo'
+    assert isinstance(request.url, str)
+
+
+def test_request_url_from_host_header():
+    request_handler = mock.Mock()
+    request_handler.server.scheme = 'http'
+    request_handler.server.server_address = ('localhost', '8000')
+    request_handler.path = '/demo'
+    request_handler.headers = MockHTTPMessage({'host': ['web-platform.test:8001']})
+
+    request = Request(request_handler)
+    assert request.url == 'http://web-platform.test:8001/demo'
+    assert isinstance(request.url, str)
diff --git a/tests/wpt/web-platform-tests/tools/wptserve/wptserve/request.py b/tests/wpt/web-platform-tests/tools/wptserve/wptserve/request.py
index a80bc0c8300..89d52a9817e 100644
--- a/tests/wpt/web-platform-tests/tools/wptserve/wptserve/request.py
+++ b/tests/wpt/web-platform-tests/tools/wptserve/wptserve/request.py
@@ -248,8 +248,12 @@ class Request(object):
         self.protocol_version = request_handler.protocol_version
         self.method = request_handler.command
 
+        # Keys and values in raw headers are native strings.
+        self._headers = None
+        self.raw_headers = request_handler.headers
+
         scheme = request_handler.server.scheme
-        host = request_handler.headers.get("Host")
+        host = self.raw_headers.get("Host")
         port = request_handler.server.server_address[1]
 
         if host is None:
@@ -262,22 +266,17 @@ class Request(object):
         self.url_base = "/"
 
         if self.request_path.startswith(scheme + "://"):
-            self.url = request_handler.path
+            self.url = self.request_path
         else:
-            self.url = "%s://%s:%s%s" % (scheme,
-                                      host,
-                                      port,
-                                      self.request_path)
+            # TODO(#23362): Stop using native strings for URLs.
+            self.url = "%s://%s:%s%s" % (
+                scheme, host, port, self.request_path)
         self.url_parts = urlsplit(self.url)
 
-        self.raw_headers = request_handler.headers
-
         self.request_line = request_handler.raw_requestline
 
-        self._headers = None
-
         self.raw_input = InputFile(request_handler.rfile,
-                                   int(self.headers.get("Content-Length", 0)))
+                                   int(self.raw_headers.get("Content-Length", 0)))
 
         self._body = None
 
@@ -303,9 +302,10 @@ class Request(object):
     @property
     def POST(self):
         if self._POST is None:
-            #Work out the post parameters
+            # Work out the post parameters
             pos = self.raw_input.tell()
             self.raw_input.seek(0)
+            # FIXME: specify encoding in Python 3.
             fs = cgi.FieldStorage(fp=self.raw_input,
                                   environ={"REQUEST_METHOD": self.method},
                                   headers=self.raw_headers,
@@ -400,7 +400,6 @@ class RequestHeaders(dict):
                 headers = [_maybe_encode(items[header])]
             dict.__setitem__(self, key, headers)
 
-
     def __getitem__(self, key):
         """Get all headers of a certain (case-insensitive) name. If there is
         more than one, the values are returned comma separated"""
@@ -409,7 +408,7 @@ class RequestHeaders(dict):
         if len(values) == 1:
             return values[0]
         else:
-            return ", ".join(values)
+            return b", ".join(values)
 
     def __setitem__(self, name, value):
         raise Exception
@@ -451,6 +450,7 @@ class RequestHeaders(dict):
         for item in self:
             yield self[item]
 
+
 class CookieValue(object):
     """Representation of cookies.
 
diff --git a/tests/wpt/web-platform-tests/url/urlsearchparams-constructor.any.js b/tests/wpt/web-platform-tests/url/urlsearchparams-constructor.any.js
index f7989f70ea0..8d855a4fd4d 100644
--- a/tests/wpt/web-platform-tests/url/urlsearchparams-constructor.any.js
+++ b/tests/wpt/web-platform-tests/url/urlsearchparams-constructor.any.js
@@ -73,6 +73,23 @@ test(function() {
     assert_false(seed.has('g'));
 }, 'URLSearchParams constructor, object.');
 
+test(function() {
+    var formData = new FormData()
+    formData.append('a', 'b')
+    formData.append('c', 'd')
+    var params = new URLSearchParams(formData);
+    assert_true(params != null, 'constructor returned non-null value.');
+    assert_equals(params.get('a'), 'b');
+    assert_equals(params.get('c'), 'd');
+    assert_false(params.has('d'));
+    // The name-value pairs are copied when created; later updates
+    // should not be observable.
+    formData.append('e', 'f');
+    assert_false(params.has('e'));
+    params.append('g', 'h');
+    assert_false(formData.has('g'));
+}, 'URLSearchParams constructor, FormData.');
+
 test(function() {
     var params = new URLSearchParams('a=b+c');
     assert_equals(params.get('a'), 'b c');
diff --git a/tests/wpt/web-platform-tests/web-animations/interfaces/Animation/commitStyles.html b/tests/wpt/web-platform-tests/web-animations/interfaces/Animation/commitStyles.html
index 19461844b7c..f16412fbcf7 100644
--- a/tests/wpt/web-platform-tests/web-animations/interfaces/Animation/commitStyles.html
+++ b/tests/wpt/web-platform-tests/web-animations/interfaces/Animation/commitStyles.html
@@ -95,9 +95,26 @@ test(t => {
 
   animation.cancel();
 
-  assert_equals(div.style.marginLeft, '20px');
+  assert_equals(getComputedStyle(div).marginLeft, '20px');
 }, 'Commits logical properties');
 
+test(t => {
+  const div = createDiv(t);
+  div.style.marginLeft = '10px';
+
+  const animation = div.animate(
+    { marginInlineStart: '20px' },
+    { duration: 1, fill: 'forwards' }
+  );
+  animation.finish();
+
+  animation.commitStyles();
+
+  animation.cancel();
+
+  assert_equals(div.style.marginLeft, '20px');
+}, 'Commits logical properties as physical properties');
+
 test(t => {
   const div = createDiv(t);
   div.style.marginLeft = '10px';
@@ -160,12 +177,32 @@ test(t => {
 
   assert_numeric_style_equals(getComputedStyle(div).width, 100);
 
-  // Changes to the font-size should have no effect
   div.style.fontSize = '20px';
-
-  assert_numeric_style_equals(getComputedStyle(div).width, 100);
+  assert_numeric_style_equals(getComputedStyle(div).width, 100,
+      "Changes to the font-size should have no effect");
 }, 'Commits em units as pixel values');
 
+test(t => {
+  const div = createDiv(t);
+  div.style.fontSize = '10px';
+
+  const animation = div.animate(
+    { lineHeight: '1.5' },
+    { duration: 1, fill: 'forwards' }
+  );
+  animation.finish();
+  animation.commitStyles();
+  animation.cancel();
+
+  assert_numeric_style_equals(getComputedStyle(div).lineHeight, 15);
+  assert_equals(div.style.lineHeight, "1.5", "line-height is committed as a relative value");
+
+  div.style.fontSize = '20px';
+  assert_numeric_style_equals(getComputedStyle(div).lineHeight, 30,
+      "Changes to the font-size should affect the committed line-height");
+
+}, 'Commits relative line-height');
+
 test(t => {
   const div = createDiv(t);
   const animation = div.animate(
@@ -188,7 +225,38 @@ test(t => {
   animation.commitStyles();
   animation.cancel();
   assert_equals(div.style.transform, 'translate(20px, 20px)');
-}, 'Commits computed transform');
+}, 'Commits transforms as a transform list');
+
+test(t => {
+  const div = createDiv(t);
+  div.style.width = '200px';
+  div.style.height = '200px';
+
+  const animation = div.animate({ transform: ["translate(100%, 0%)", "scale(3)"] }, 1000);
+  animation.currentTime = 500;
+  animation.commitStyles();
+  animation.cancel();
+
+  // TODO(https://github.com/w3c/csswg-drafts/issues/2854):
+  // We can't check the committed value directly since it is not specced yet in this case,
+  // but it should still produce the correct resolved value.
+  assert_equals(getComputedStyle(div).transform, "matrix(2, 0, 0, 2, 100, 0)",
+      "Resolved transform is correct after commit.");
+}, 'Commits matrix-interpolated relative transforms');
+
+test(t => {
+  const div = createDiv(t);
+  div.style.width = '200px';
+  div.style.height = '200px';
+
+  const animation = div.animate({ transform: ["none", "none"] }, 1000);
+  animation.currentTime = 500;
+  animation.commitStyles();
+  animation.cancel();
+
+  assert_equals(div.style.transform, "none",
+      "Resolved transform is correct after commit.");
+}, 'Commits "none" transform');
 
 promise_test(async t => {
   const div = createDiv(t);
diff --git a/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html
new file mode 100644
index 00000000000..c1755cd1559
--- /dev/null
+++ b/tests/wpt/web-platform-tests/webaudio/the-audio-api/the-audioparam-interface/k-rate-dynamics-compressor-connections.html
@@ -0,0 +1,145 @@
+<!doctype html>
+<html>
+  <head>
+    <title>k-rate AudioParams with inputs for DynamicsCompressorNode</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+    <script src="/webaudio/resources/audit.js"></script>
+    <script src="/webaudio/resources/audit-util.js"></script>
+  </head>
+
+  <body>
+    <script>
+      let audit = Audit.createTaskRunner();
+
+      // Fairly abitrary sampleRate and somewhat duration
+      const sampleRate = 48000;
+      const testDuration = 0.25;
+
+      ['attack', 'knee', 'ratio', 'release', 'threshold'].forEach(param => {
+        audit.define(
+            {label: param, description: `Dynamics compressor ${param}`},
+            async (task, should) => {
+              await doTest(should, {prefix: task.label, paramName: param});
+              task.done();
+            });
+      });
+
+      audit.run();
+
+      async function doTest(should, options) {
+        // Test k-rate automation of DynamicsCompressorNode with connected
+        // input.
+        //
+        // A reference compressor node is created with an automation on the
+        // selected AudioParam. For simplicity, we just use a linear ramp from
+        // the minValue to the maxValue of the AudioParam.
+        //
+        // The test node has an input signal connected to the AudioParam.  This
+        // input signal is created to match the automation on the reference
+        // node.
+        //
+        // Finally, the output from the two nodes must be identical if k-rate
+        // inputs are working correctly.
+        //
+        // Options parameter is a dictionary with the following required
+        // members:
+        //   prefix    - prefix to use for the messages.
+        //   paramName - Name of the AudioParam to be tested
+
+        let {prefix, paramName} = options;
+
+        let context = new OfflineAudioContext({
+          numberOfChannels: 2,
+          sampleRate: sampleRate,
+          length: testDuration * sampleRate
+        });
+
+        let merger = new ChannelMergerNode(
+            context, {numberOfInputs: context.destination.channelCount});
+        merger.connect(context.destination);
+
+        // Use an oscillator for the source.  Pretty arbitrary parameters.
+        let src =
+            new OscillatorNode(context, {type: 'sawtooth', frequency: 440});
+
+        // Create the reference and test nodes.
+        let refNode;
+        let tstNode;
+
+        should(
+            () => refNode = new DynamicsCompressorNode(context),
+            `${prefix}: refNode = new DynamicsCompressorNode(context)`)
+            .notThrow();
+
+        let tstOptions = {};
+        tstOptions[paramName] = refNode[paramName].minValue;
+        should(
+            () => tstNode = new DynamicsCompressorNode(context, tstOptions),
+            `${prefix}: tstNode = new DynamicsCompressorNode(context, ${
+                JSON.stringify(tstOptions)})`)
+            .notThrow();
+
+
+        // Automate the AudioParam of the reference node with a linear ramp
+        should(
+            () => refNode[paramName].setValueAtTime(
+                refNode[paramName].minValue, 0),
+            `${prefix}: refNode[${paramName}].setValueAtTime(refNode[${
+                paramName}].minValue, 0)`)
+            .notThrow();
+
+        should(
+            () => refNode[paramName].linearRampToValueAtTime(
+                refNode[paramName].maxValue, testDuration),
+            `${prefix}: refNode[${paramName}].linearRampToValueAtTime(refNode[${
+                paramName}].minValue, ${testDuration})`)
+            .notThrow();
+
+
+        // Create the input node and automate it so that it's output when added
+        // to the intrinsic value of the AudioParam we get the same values as
+        // the automations on the ference node.  We need to do it this way
+        // because the ratio AudioParam has a nominal range of [1, 20] so we
+        // can't just set the value to 0, which is what we'd normally do.
+        let mod;
+        should(
+            () => mod = new ConstantSourceNode(context, {offset: 0}),
+            `${prefix}: mod = new ConstantSourceNode(context, {offset: 0})`)
+            .notThrow();
+        let endValue =
+            refNode[paramName].maxValue - refNode[paramName].minValue;
+        should(
+            () => mod.offset.setValueAtTime(0, 0),
+            `${prefix}: mod.offset.setValueAtTime(0, 0)`)
+            .notThrow();
+        should(
+            () => mod.offset.linearRampToValueAtTime(endValue, testDuration),
+            `${prefix}: mod.offset.linearRampToValueAtTime(${endValue}, ${
+                testDuration})`)
+            .notThrow();
+
+        // Connect up everything.
+        should(
+            () => mod.connect(tstNode[paramName]),
+            `${prefix}: mod.connect(tstNode[${paramName}])`)
+            .notThrow();
+
+        src.connect(refNode).connect(merger, 0, 0);
+        src.connect(tstNode).connect(merger, 0, 1);
+
+        // Go!
+        src.start();
+        mod.start();
+
+        const buffer = await context.startRendering();
+        let expected = buffer.getChannelData(0);
+        let actual = buffer.getChannelData(1);
+
+        // The expected and actual results must be EXACTLY the same.
+        should(actual, `k-rate ${paramName} AudioParam with input`)
+            .beCloseToArray(expected, {absoluteThreshold: 0});
+      }
+    </script>
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/webrtc/RTCDataChannel-close.html b/tests/wpt/web-platform-tests/webrtc/RTCDataChannel-close.html
index a417d66d9aa..b8feea332ad 100644
--- a/tests/wpt/web-platform-tests/webrtc/RTCDataChannel-close.html
+++ b/tests/wpt/web-platform-tests/webrtc/RTCDataChannel-close.html
@@ -88,4 +88,33 @@ promise_test(async t => {
   assert_equals(error.name, 'OperationError');
 }, 'Close peerconnection causes close event and error to be called');
 
+promise_test(async t => {
+  let pc1 = new RTCPeerConnection();
+  t.add_cleanup(() => pc1.close());
+  let [channel1, channel2] = await createDataChannelPair(pc1);
+  // The expected sequence of events when closing a DC is that
+  // channel1 goes to closing, channel2 fires onclose, and when
+  // the close is confirmed, channel1 fires onclose.
+  // After that, no more events should fire.
+  channel1.onerror = t.unreached_func();
+  let close2Handler = new Promise(resolve => {
+    channel2.onclose = event => {
+      resolve();
+    };
+  });
+  let close1Handler = new Promise(resolve => {
+    channel1.onclose = event => {
+      resolve();
+    };
+  });
+  channel1.close();
+  await close2Handler;
+  await close1Handler;
+  channel1.onclose = t.unreached_func();
+  channel2.onclose = t.unreached_func();
+  channel2.onerror = t.unreached_func();
+  pc1.close();
+  await new Promise(resolve => t.step_timeout(resolve, 10));
+}, 'Close peerconnection after DC close causes no events');
+
 </script>
diff --git a/tests/wpt/webgl/meta/conformance2/rendering/draw-buffers.html.ini b/tests/wpt/webgl/meta/conformance2/rendering/draw-buffers.html.ini
index 82e6eac043c..3c69e83fd9b 100644
--- a/tests/wpt/webgl/meta/conformance2/rendering/draw-buffers.html.ini
+++ b/tests/wpt/webgl/meta/conformance2/rendering/draw-buffers.html.ini
@@ -110,3 +110,18 @@
   [WebGL test #52: attachment 7 should be 0,255,0,255\nat (0, 0) expected: 0,255,0,255 was 0,0,0,0]
     expected: FAIL
 
+  [WebGL test #52: attachment 7 should be 0,255,0,255\nat (4, 0) expected: 0,255,0,255 was 255,0,0,0]
+    expected: FAIL
+
+  [WebGL test #42: attachment 5 should be 0,255,0,255\nat (0, 0) expected: 0,255,0,255 was 0,0,0,0]
+    expected: FAIL
+
+  [WebGL test #40: attachment 3 should be 0,255,0,255\nat (0, 0) expected: 0,255,0,255 was 0,0,0,0]
+    expected: FAIL
+
+  [WebGL test #39: attachment 2 should be 0,255,0,255\nat (0, 0) expected: 0,255,0,255 was 0,0,0,0]
+    expected: FAIL
+
+  [WebGL test #41: attachment 4 should be 0,255,0,255\nat (0, 0) expected: 0,255,0,255 was 0,0,0,0]
+    expected: FAIL
+