diff --git a/tests/wpt/metadata-layout-2020/FileAPI/url/url-charset.window.js.ini b/tests/wpt/metadata-layout-2020/FileAPI/url/url-charset.window.js.ini
new file mode 100644
index 00000000000..a9005e45d6e
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/FileAPI/url/url-charset.window.js.ini
@@ -0,0 +1,8 @@
+[url-charset.window.html]
+  expected: TIMEOUT
+  [Blob charset should override any auto-detected charset.]
+    expected: TIMEOUT
+
+  [Blob charset should override <meta charset>.]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
similarity index 67%
rename from tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini
rename to tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
index f29da48a2a0..4bfb0c2053a 100644
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
@@ -1,4 +1,4 @@
-[hit-test-floats-003.html]
+[hit-test-floats-004.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/CSS2/linebox/inline-negative-margin-001.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/linebox/inline-negative-margin-001.html.ini
index 5643f1a8367..5e4d523cef9 100644
--- a/tests/wpt/metadata-layout-2020/css/CSS2/linebox/inline-negative-margin-001.html.ini
+++ b/tests/wpt/metadata-layout-2020/css/CSS2/linebox/inline-negative-margin-001.html.ini
@@ -11,36 +11,9 @@
   [[data-expected-height\] 2]
     expected: FAIL
 
-  [[data-expected-height\] 4]
-    expected: FAIL
-
   [[data-expected-height\] 1]
     expected: FAIL
 
-  [[data-expected-height\] 10]
-    expected: FAIL
-
   [[data-expected-height\] 2]
     expected: FAIL
 
-  [[data-expected-height\] 5]
-    expected: FAIL
-
-  [[data-expected-height\] 6]
-    expected: FAIL
-
-  [[data-expected-height\] 9]
-    expected: FAIL
-
-  [[data-expected-height\] 8]
-    expected: FAIL
-
-  [[data-expected-height\] 13]
-    expected: FAIL
-
-  [[data-expected-height\] 12]
-    expected: FAIL
-
-  [[data-expected-height\] 11]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/css-backgrounds/background-attachment-353.html.ini b/tests/wpt/metadata-layout-2020/css/css-backgrounds/background-attachment-353.html.ini
new file mode 100644
index 00000000000..d1af9d7d555
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/css-backgrounds/background-attachment-353.html.ini
@@ -0,0 +1,2 @@
+[background-attachment-353.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata-layout-2020/css/css-flexbox/grid-flex-item-005.html.ini b/tests/wpt/metadata-layout-2020/css/css-flexbox/grid-flex-item-005.html.ini
new file mode 100644
index 00000000000..3fe332060a7
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/css-flexbox/grid-flex-item-005.html.ini
@@ -0,0 +1,2 @@
+[grid-flex-item-005.html]
+  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 f8e7e539aae..4a1e8110f6f 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
@@ -2,6 +2,3 @@
   [Hit test intersecting scaled box]
     expected: FAIL
 
-  [Hit test within unscaled box]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/CaretPosition-001.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/CaretPosition-001.html.ini
deleted file mode 100644
index 4c79907309b..00000000000
--- a/tests/wpt/metadata-layout-2020/css/cssom-view/CaretPosition-001.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[CaretPosition-001.html]
-  [Element at (400, 100)]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/client-props-root.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/client-props-root.html.ini
new file mode 100644
index 00000000000..cbdf6bf109c
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/cssom-view/client-props-root.html.ini
@@ -0,0 +1,4 @@
+[client-props-root.html]
+  [client* properties on the root element]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/matchMedia-display-none-iframe.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/matchMedia-display-none-iframe.html.ini
new file mode 100644
index 00000000000..e6e1f29e274
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/cssom-view/matchMedia-display-none-iframe.html.ini
@@ -0,0 +1,2 @@
+[matchMedia-display-none-iframe.html]
+  expected: ERROR
diff --git a/tests/wpt/metadata-layout-2020/custom-elements/reactions/HTMLMediaElement.html.ini b/tests/wpt/metadata-layout-2020/custom-elements/reactions/HTMLMediaElement.html.ini
deleted file mode 100644
index 2ca05f57bb0..00000000000
--- a/tests/wpt/metadata-layout-2020/custom-elements/reactions/HTMLMediaElement.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[HTMLMediaElement.html]
-  expected: TIMEOUT
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 a3f0e3742dd..665e9b4f334 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
@@ -312,24 +312,24 @@
   [Response: combined response Content-Type: text/html;" \\" text/plain ";charset=GBK]
     expected: NOTRUN
 
-  [<iframe>: separate response Content-Type: text/html;x=" 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>: separate response Content-Type: text/html */*;charset=gbk]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*]
-    expected: FAIL
-
   [<iframe>: combined response Content-Type: text/html;x=" text/plain]
     expected: FAIL
 
+  [<iframe>: combined response Content-Type: text/html */*]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: text/html;" \\" text/plain]
+    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 b2ffc8abf78..d2df9b78483 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
@@ -56,6 +56,3 @@
   [separate text/javascript x/x]
     expected: FAIL
 
-  [separate text/javascript error]
-    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 30e1b851fd4..7277f622b20 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
@@ -11,3 +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%20%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
deleted file mode 100644
index 87b07c3e670..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[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_2.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
deleted file mode 100644
index 75d75b4cda2..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_2.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
deleted file mode 100644
index 51f8272a6de..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_3.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
new file mode 100644
index 00000000000..735a9a75a2a
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
@@ -0,0 +1,2 @@
+[cross-origin-objects-on-new-window.html]
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata-layout-2020/html/browsers/windows/embedded-opener-remove-frame.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/windows/embedded-opener-remove-frame.html.ini
index 9a85a905394..8e2a63e3b7f 100644
--- a/tests/wpt/metadata-layout-2020/html/browsers/windows/embedded-opener-remove-frame.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/browsers/windows/embedded-opener-remove-frame.html.ini
@@ -1,4 +1,5 @@
 [embedded-opener-remove-frame.html]
+  expected: CRASH
   [opener of discarded nested browsing context]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini
index 42ebcc9d57e..92008abe69f 100644
--- a/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini
@@ -1,5 +1,4 @@
 [iframe_sandbox_popups_escaping-1.html]
-  expected: TIMEOUT
   [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-2.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
index 4df5d7a35de..daa518bd0e3 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
@@ -1,4 +1,5 @@
 [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: 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 295031c1812..338d283eb0e 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
@@ -1,5 +1,4 @@
 [iframe_sandbox_popups_escaping-3.html]
-  expected: TIMEOUT
   [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_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 3080be9afc0..d913fcbb129 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: CRASH
+  expected: TIMEOUT
   [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 7a36937927c..f4f994c5d6f 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
@@ -1,4 +1,5 @@
 [iframe_sandbox_popups_nonescaping-3.html]
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
-    expected: FAIL
+    expected: NOTRUN
 
diff --git a/tests/wpt/metadata-layout-2020/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini b/tests/wpt/metadata-layout-2020/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
new file mode 100644
index 00000000000..bcd2fd0eab8
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
@@ -0,0 +1,4 @@
+[077.html]
+  [ adding several types of scripts through the DOM and removing some of them confuses scheduler ]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
deleted file mode 100644
index fca4d908c89..00000000000
--- a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[module-static-import-delayed.html]
-  [document.write in an imported module]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
index 57744023f73..58c9d7f8c0c 100644
--- a/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
+++ b/tests/wpt/metadata-layout-2020/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
@@ -1,5 +1,5 @@
 [ignore-opens-during-unload.window.html]
-  expected: CRASH
+  expected: TIMEOUT
   [document.open should bail out when ignore-opens-during-unload is greater than 0 during visibilitychange event (open(parent) while unloading parent and child)]
     expected: TIMEOUT
 
diff --git a/tests/wpt/metadata-layout-2020/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini b/tests/wpt/metadata-layout-2020/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini
index dbec6f2c2ff..450c88bd32b 100644
--- a/tests/wpt/metadata-layout-2020/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini
+++ b/tests/wpt/metadata-layout-2020/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini
@@ -3,3 +3,6 @@
   [The incumbent settings object while executing the compiled callback via Web IDL's invoke must be that of the node document]
     expected: TIMEOUT
 
+  [The entry settings object while executing the compiled callback via Web IDL's invoke must be that of the node document]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/wasm/jsapi/namespace-object-class-string.any.js.ini b/tests/wpt/metadata-layout-2020/wasm/jsapi/constructor/toStringTag.any.js.ini
similarity index 87%
rename from tests/wpt/metadata/wasm/jsapi/namespace-object-class-string.any.js.ini
rename to tests/wpt/metadata-layout-2020/wasm/jsapi/constructor/toStringTag.any.js.ini
index 8126018bc63..a5d04e20667 100644
--- a/tests/wpt/metadata/wasm/jsapi/namespace-object-class-string.any.js.ini
+++ b/tests/wpt/metadata-layout-2020/wasm/jsapi/constructor/toStringTag.any.js.ini
@@ -1,4 +1,4 @@
-[namespace-object-class-string.any.html]
+[toStringTag.any.html]
   [Object.prototype.toString applied after deleting @@toStringTag]
     expected: FAIL
 
@@ -9,7 +9,7 @@
     expected: FAIL
 
 
-[namespace-object-class-string.any.worker.html]
+[toStringTag.any.worker.html]
   [Object.prototype.toString applied after deleting @@toStringTag]
     expected: FAIL
 
diff --git a/tests/wpt/metadata-layout-2020/workers/constructors/Worker/Worker-constructor.html.ini b/tests/wpt/metadata-layout-2020/workers/constructors/Worker/Worker-constructor.html.ini
new file mode 100644
index 00000000000..80f9a4f15b8
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/workers/constructors/Worker/Worker-constructor.html.ini
@@ -0,0 +1,2 @@
+[Worker-constructor.html]
+  expected: ERROR
diff --git a/tests/wpt/metadata/FileAPI/url/url-charset.window.js.ini b/tests/wpt/metadata/FileAPI/url/url-charset.window.js.ini
new file mode 100644
index 00000000000..a9005e45d6e
--- /dev/null
+++ b/tests/wpt/metadata/FileAPI/url/url-charset.window.js.ini
@@ -0,0 +1,8 @@
+[url-charset.window.html]
+  expected: TIMEOUT
+  [Blob charset should override any auto-detected charset.]
+    expected: TIMEOUT
+
+  [Blob charset should override <meta charset>.]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index e4dd8e1a26b..09797eaab78 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -10591,6 +10591,34 @@
      ]
     },
     "css-pseudo": {
+     "active-selection-001-manual.html": [
+      "55001fe379f0dafe1f4690bbe8fb4a115bb0623c",
+      [
+       null,
+       {}
+      ]
+     ],
+     "active-selection-002-manual.html": [
+      "01cec72b2d4dfeab99fc2a6f8afd3b701a698b30",
+      [
+       null,
+       {}
+      ]
+     ],
+     "active-selection-003-manual.html": [
+      "c56a301ef3a475530cce9b4b01a008577f6bd88a",
+      [
+       null,
+       {}
+      ]
+     ],
+     "active-selection-004-manual.html": [
+      "ac7ba7da327df4705c3b71bdebcbb9cc08a4c5ae",
+      [
+       null,
+       {}
+      ]
+     ],
      "grammar-error-002-manual.html": [
       "3cec3df0adb41f5a7345458dee3090175f85f285",
       [
@@ -118242,6 +118270,19 @@
        {}
       ]
      ],
+     "background-attachment-353.html": [
+      "c5ac06c0f57f25a390c29d05622b1fbb09b667eb",
+      [
+       null,
+       [
+        [
+         "/css/reference/ref-filled-green-100px-square.xht",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "background-attachment-local": {
       "attachment-local-clipping-color-1.html": [
        "8cb76ee89c941bb0b78ad90106981a888b46244f",
@@ -139183,6 +139224,19 @@
        {}
       ]
      ],
+     "grid-flex-item-005.html": [
+      "95c57d1429e5de2a138571435134152c2c33561b",
+      [
+       null,
+       [
+        [
+         "/css/reference/ref-filled-green-100px-square-only.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "image-items-flake-001.html": [
       "90319f1ad83d26d414d8ddcd4a9ab59042a4bd62",
       [
@@ -162116,6 +162170,71 @@
      ]
     },
     "css-pseudo": {
+     "active-selection-011.html": [
+      "57335dc52d9ce2460e3d6db867bd41fea778e1dd",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/reference/active-selection-011-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "active-selection-012.html": [
+      "e40b0d2a0d2a94e64e8d79be33f3c51b89182aed",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/reference/active-selection-012-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "active-selection-014.html": [
+      "1bc244c800a82050d20acf28aa978dd478fb7fa4",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/reference/active-selection-014-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "active-selection-016.html": [
+      "e5a56afe02280bc5eae0821ee8135aeab6e0401e",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/reference/active-selection-016-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
+     "active-selection-018.html": [
+      "ee7871c9503d45a3e0a0fbcff7e368d4557e33c3",
+      [
+       null,
+       [
+        [
+         "/css/css-pseudo/reference/active-selection-011-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "active-selection-021.html": [
       "2061385d6c564c32ff2e36fc096df5b633d7ec2a",
       [
@@ -163386,7 +163505,7 @@
       ]
      ],
      "selection-intercharacter-011.html": [
-      "70ab69fb492070103f2d5caa6a8f60035f0392e8",
+      "a8f02b10e0fc59264e79e0e94264451eb75366eb",
       [
        null,
        [
@@ -163399,7 +163518,7 @@
       ]
      ],
      "selection-intercharacter-012.html": [
-      "a04fc33e2fe918f8555583d9da2c48197037dc82",
+      "8dc665b77c9529f18d65b06042f7ec14d3e57084",
       [
        null,
        [
@@ -247827,7 +247946,7 @@
   },
   "support": {
    ".azure-pipelines.yml": [
-    "215f3d8ffd8e2e3ef2d2abdde4e2a6e7b5058fe2",
+    "cbd7b33b5d421e8dda64adfd8e25383e82173a5b",
     []
    ],
    ".codecov.yml": [
@@ -270919,7 +271038,7 @@
       []
      ],
      "cookie_helper.py": [
-      "cf48f26eed1661b8e0f85a4ea8029b2f0b8d2e2d",
+      "b88b25c701639dfdf92596c6523bf310fe8dcca1",
       []
      ],
      "empty_sw.js": [
@@ -291915,6 +292034,10 @@
        "70437d7bda2b56a921b523d4a81ca4df7be4321d",
        []
       ],
+      "100x100-gr-rr.png": [
+       "dfd0593e3c4ef9b6c75622e6d7dffca3ff114b36",
+       []
+      ],
       "100x100-green-with-red-corners.png": [
        "a193937c0d017b4b497a68874468fa92123f223e",
        []
@@ -306155,6 +306278,22 @@
       []
      ],
      "reference": {
+      "active-selection-011-ref.html": [
+       "5c5fb091b85bb4a8d7d7025aac4caeafd34ed65f",
+       []
+      ],
+      "active-selection-012-ref.html": [
+       "2faa69510d8bc4f867301955be306b53d2a4ed7b",
+       []
+      ],
+      "active-selection-014-ref.html": [
+       "4a9dd309a0141d6b3950e73ff17ffdd468e14955",
+       []
+      ],
+      "active-selection-016-ref.html": [
+       "cd80adb3c3be45234bb3e89f42086dd30432cdb9",
+       []
+      ],
       "active-selection-021-ref.html": [
        "7790a3fad8a36f1709fea6a4155ed5af0f3c49d7",
        []
@@ -306176,11 +306315,11 @@
        []
       ],
       "selection-intercharacter-011-ref.html": [
-       "b0c60408f760b562b98fcb4ff2682fb1e3638452",
+       "b3fa3531b3ed9c1bbb83f7ed5349d3ba792cebcf",
        []
       ],
       "selection-intercharacter-012-ref.html": [
-       "38650c90b4096ddac99543aeca2405ac4f288969",
+       "3ead305bfb8eaf08424b789f40efa73c26d8dfe3",
        []
       ],
       "selection-textarea-011-ref.html": [
@@ -306200,6 +306339,14 @@
       "100x100-red.png": [
        "57bf3ddc5213d06e0975de38f330ffb7c441b268",
        []
+      ],
+      "select-custom.cur": [
+       "0a1f5dd51458223ce9213487ebcea627cdf75a4d",
+       []
+      ],
+      "select-custom.png": [
+       "344aacee6afe29536d1263a3a24cb47a7f7b8786",
+       []
       ]
      },
      "textpath-selection-011-ref.html": [
@@ -325866,7 +326013,7 @@
        []
       ],
       "long-wav.py": [
-       "8af2aca8a959b39c7cbd91704e9228a119f2b2d8",
+       "be7df7b83d8723ffd8c977d3f4b5c42a23d7918a",
        []
       ],
       "partial-script.py": [
@@ -325928,6 +326075,22 @@
      ]
     }
    },
+   "focus": {
+    "support": {
+     "focus-restoration-in-different-site-iframes-inner.html": [
+      "903b0c02858520dd1d3af7f95b82033fc5509585",
+      []
+     ],
+     "focus-restoration-in-different-site-iframes-other.html": [
+      "b302b90938789e2090b99bb0c223080c68962e37",
+      []
+     ],
+     "focus-restoration-in-different-site-iframes-outer.sub.html": [
+      "91ffed1107580585831313347ebd04ed3dd75d8d",
+      []
+     ]
+    }
+   },
    "fonts": {
     "AD.woff": [
      "3df8ea8efdabd11bc45fdcc6d4f3fec771be6650",
@@ -329919,7 +330082,7 @@
         []
        ],
        "dispatcher.py": [
-        "2f1cf1bd4cf4f4d229de09bfb6da369f6b18adc2",
+        "2617361b0b369bd9efd3aedd42a88f8f46906fe3",
         []
        ],
        "executor.html": [
@@ -335890,7 +336053,7 @@
          []
         ],
         "download_stash.py": [
-         "95256a2457aeb40dea30f5d43e713bca09f45c1f",
+         "a95fe37dd88e7db829edf3d260d3bdc3b7a7460e",
          []
         ],
         "iframe-that-checks-contentDocument.html": [
@@ -339660,7 +339823,7 @@
      []
     ],
     "geolocation-API.idl": [
-     "e8dd1526fd071eb0ffe32f21d624d41c0ccfd1cd",
+     "8bce6413816583e40feb941c4903d7be9346c8a2",
      []
     ],
     "geolocation-sensor.idl": [
@@ -340293,7 +340456,7 @@
     ]
    },
    "lint.ignore": [
-    "40b7cb2c2180de0227a5803f4fd6b69ee8dc2c78",
+    "e52c2ae457638a90404fe8e4e200962314b6d441",
     []
    ],
    "loading": {
@@ -350123,7 +350286,7 @@
       []
      ],
      "pr_preview.py": [
-      "ba5997f68a615f49322ac009a15aebf0a5a071f3",
+      "2396e9b8aee8a166c3b9321c7e9ec2e8f9b549c0",
       []
      ],
      "run_tc.py": [
@@ -350204,7 +350367,7 @@
        []
       ],
       "test_pr_preview.py": [
-       "2d9966fc8cf4187913adce8609ee750ade1b9797",
+       "13aef50866312998855e8c46579e8a4d8443dc24",
        []
       ]
      },
@@ -356545,7 +356708,7 @@
       []
      ],
      "browser.py": [
-      "6db3415a480c7e62dca111652c388aa83471d1da",
+      "6abe151948438beaf4cd252b44d63d751587b1ec",
       []
      ],
      "commands.json": [
@@ -356598,7 +356761,7 @@
        []
       ],
       "test_install.py": [
-       "7d55d419c1401aca559b92b0aedfdfb83c6c1bc5",
+       "d1abbed142eb5af606e606057786092dd1f01a7d",
        []
       ],
       "test_markdown.py": [
@@ -376292,7 +376455,7 @@
      ]
     ],
     "setSinkId.https.html": [
-     "b1f703a9350bf557f0d38911a09c09a9d02eaa3a",
+     "80e2832e970c0696e132e14d7fd1d8ae2d456d03",
      [
       null,
       {}
@@ -395154,6 +395317,13 @@
         {}
        ]
       ],
+      "grid-place-content-001.html": [
+       "49bb63928be72401c588eb1816f5a1ce1d0aade3",
+       [
+        null,
+        {}
+       ]
+      ],
       "grid-row-axis-alignment-positioned-items-001.html": [
        "b76e808da5f7156ee2206d8aecb36990df502037",
        [
@@ -411687,6 +411857,13 @@
        {}
       ]
      ],
+     "client-props-root.html": [
+      "875522ec7c18a5a5ffc84eb71a9aa50382e10733",
+      [
+       null,
+       {}
+      ]
+     ],
      "cssom-getBoundingClientRect-001.html": [
       "7d96540adfe95205a770c232473e0c1268e609e2",
       [
@@ -436131,6 +436308,15 @@
      ]
     }
    },
+   "focus": {
+    "focus-restoration-in-different-site-iframes.html": [
+     "3de05455651aef8e37e99aa33877c4e5905103ac",
+     [
+      null,
+      {}
+     ]
+    ]
+   },
    "forced-colors-mode": {
     "forced-colors-mode-03.html": [
      "ebe42e4e7502a327849fe2c65924480e00de4399",
@@ -439111,6 +439297,13 @@
         {}
        ]
       ],
+      "window-open-invalid-url.html": [
+       "cabc143b9db769c254631702260ffa5f16a619b7",
+       [
+        null,
+        {}
+       ]
+      ],
       "window-open-noopener.html": [
        "c3c706605492c5c81bc296054eb98c280492527f",
        [
@@ -457306,7 +457499,7 @@
         ]
        ],
        "property.https.html": [
-        "67aebb5838bb5de62e8628836655f2a480b48b2d",
+        "625fc94117768b792a27c148f609ccccef61507b",
         [
          null,
          {
@@ -476695,6 +476888,13 @@
       {}
      ]
     ],
+    "move-transformed.html": [
+     "c9cdb9954b7002940559d8417e62afe69916428f",
+     [
+      null,
+      {}
+     ]
+    ],
     "multi-clip-visual-rect.html": [
      "36475d4c826c11807e9c0a7fbf4457c33c92c2c0",
      [
@@ -476813,6 +477013,13 @@
       {}
      ]
     ],
+    "transform-change.html": [
+     "fd9657a71455629f856e53b8fa20aec1a3008e73",
+     [
+      null,
+      {}
+     ]
+    ],
     "transform.html": [
      "7ac1c8cafde664f6a39c9d0a88e0a5d76753d85f",
      [
@@ -479370,7 +479577,7 @@
      ]
     ],
     "MediaDevices-getUserMedia.https.html": [
-     "693f3bd11cfaa6be7ca21bae110467c265be5a07",
+     "f410b262cf5b419d8e056a805a46c518ea45c493",
      [
       null,
       {}
@@ -479526,7 +479733,7 @@
      ]
     ],
     "idlharness.https.window.js": [
-     "b10e8dbb046d656e4b06c3572fb4ee069c9e0897",
+     "ee5fb483c120ca273e61cefb7bc7d8be906c3355",
      [
       "mediacapture-streams/idlharness.https.window.html",
       {
@@ -516648,6 +516855,43 @@
         }
        ]
       ],
+      "toStringTag.any.js": [
+       "9c0d346bc7e1e193e16df6d211a578e5ac9509a4",
+       [
+        null,
+        {
+         "jsshell": true,
+         "script_metadata": [
+          [
+           "global",
+           "window,dedicatedworker,jsshell"
+          ]
+         ]
+        }
+       ],
+       [
+        "wasm/jsapi/constructor/toStringTag.any.html",
+        {
+         "script_metadata": [
+          [
+           "global",
+           "window,dedicatedworker,jsshell"
+          ]
+         ]
+        }
+       ],
+       [
+        "wasm/jsapi/constructor/toStringTag.any.worker.html",
+        {
+         "script_metadata": [
+          [
+           "global",
+           "window,dedicatedworker,jsshell"
+          ]
+         ]
+        }
+       ]
+      ],
       "validate.any.js": [
        "8b4f4582ab2987732d404994899e9a77662e2a32",
        [
@@ -517762,17 +518006,6 @@
        ]
       ]
      },
-     "namespace-object-class-string.any.js": [
-      "2f63aca2c55e5b404b72474a43a9631dd3ae57be",
-      [
-       "wasm/jsapi/namespace-object-class-string.any.html",
-       {}
-      ],
-      [
-       "wasm/jsapi/namespace-object-class-string.any.worker.html",
-       {}
-      ]
-     ],
      "proto-from-ctor-realm.html": [
       "72931cca77cf2af6e06616af32b4608fb02d38c0",
       [
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
similarity index 67%
rename from tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini
rename to tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
index f29da48a2a0..4bfb0c2053a 100644
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini
+++ b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
@@ -1,4 +1,4 @@
-[hit-test-floats-003.html]
+[hit-test-floats-004.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/CSS2/linebox/inline-negative-margin-001.html.ini b/tests/wpt/metadata/css/CSS2/linebox/inline-negative-margin-001.html.ini
index 94a3570d26b..076c791cd3d 100644
--- a/tests/wpt/metadata/css/CSS2/linebox/inline-negative-margin-001.html.ini
+++ b/tests/wpt/metadata/css/CSS2/linebox/inline-negative-margin-001.html.ini
@@ -8,6 +8,9 @@
   [[data-expected-height\] 3]
     expected: FAIL
 
-  [[data-expected-height\] 4]
+  [[data-expected-height\] 1]
+    expected: FAIL
+
+  [[data-expected-height\] 2]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/css/css-backgrounds/background-attachment-353.html.ini b/tests/wpt/metadata/css/css-backgrounds/background-attachment-353.html.ini
new file mode 100644
index 00000000000..d1af9d7d555
--- /dev/null
+++ b/tests/wpt/metadata/css/css-backgrounds/background-attachment-353.html.ini
@@ -0,0 +1,2 @@
+[background-attachment-353.html]
+  expected: FAIL
diff --git a/tests/wpt/metadata/css/css-flexbox/grid-flex-item-005.html.ini b/tests/wpt/metadata/css/css-flexbox/grid-flex-item-005.html.ini
new file mode 100644
index 00000000000..3fe332060a7
--- /dev/null
+++ b/tests/wpt/metadata/css/css-flexbox/grid-flex-item-005.html.ini
@@ -0,0 +1,2 @@
+[grid-flex-item-005.html]
+  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 f8e7e539aae..4a1e8110f6f 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
@@ -2,6 +2,3 @@
   [Hit test intersecting scaled box]
     expected: FAIL
 
-  [Hit test within unscaled box]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/cssom-view/CaretPosition-001.html.ini b/tests/wpt/metadata/css/cssom-view/CaretPosition-001.html.ini
deleted file mode 100644
index 4c79907309b..00000000000
--- a/tests/wpt/metadata/css/cssom-view/CaretPosition-001.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[CaretPosition-001.html]
-  [Element at (400, 100)]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/cssom-view/client-props-root.html.ini b/tests/wpt/metadata/css/cssom-view/client-props-root.html.ini
new file mode 100644
index 00000000000..cbdf6bf109c
--- /dev/null
+++ b/tests/wpt/metadata/css/cssom-view/client-props-root.html.ini
@@ -0,0 +1,4 @@
+[client-props-root.html]
+  [client* properties on the root element]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/cssom-view/matchMedia-display-none-iframe.html.ini b/tests/wpt/metadata/css/cssom-view/matchMedia-display-none-iframe.html.ini
new file mode 100644
index 00000000000..e6e1f29e274
--- /dev/null
+++ b/tests/wpt/metadata/css/cssom-view/matchMedia-display-none-iframe.html.ini
@@ -0,0 +1,2 @@
+[matchMedia-display-none-iframe.html]
+  expected: ERROR
diff --git a/tests/wpt/metadata/custom-elements/reactions/HTMLMediaElement.html.ini b/tests/wpt/metadata/custom-elements/reactions/HTMLMediaElement.html.ini
deleted file mode 100644
index 2ca05f57bb0..00000000000
--- a/tests/wpt/metadata/custom-elements/reactions/HTMLMediaElement.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[HTMLMediaElement.html]
-  expected: TIMEOUT
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 a012d413504..2629b039767 100644
--- a/tests/wpt/metadata/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
@@ -312,24 +312,24 @@
   [fetch(): separate response Content-Type: text/plain ]
     expected: NOTRUN
 
-  [<iframe>: separate response Content-Type: text/html;x=" 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>: separate response Content-Type: text/html */*;charset=gbk]
-    expected: FAIL
-
   [<iframe>: separate response Content-Type: text/html */*]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/plain */*]
-    expected: FAIL
-
   [<iframe>: combined response Content-Type: text/html;x=" text/plain]
     expected: FAIL
 
+  [<iframe>: combined response Content-Type: text/html */*]
+    expected: FAIL
+
+  [<iframe>: combined response Content-Type: text/html;" \\" text/plain]
+    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 b2ffc8abf78..d2df9b78483 100644
--- a/tests/wpt/metadata/fetch/content-type/script.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/script.window.js.ini
@@ -56,6 +56,3 @@
   [separate text/javascript x/x]
     expected: FAIL
 
-  [separate text/javascript error]
-    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 30e1b851fd4..7277f622b20 100644
--- a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,3 +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%20%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
deleted file mode 100644
index 87b07c3e670..00000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_1.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[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_2.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
deleted file mode 100644
index 75d75b4cda2..00000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_2.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
deleted file mode 100644
index 51f8272a6de..00000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_3.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_3.html]
-  [Multiple history traversals, last would be aborted]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini b/tests/wpt/metadata/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
new file mode 100644
index 00000000000..735a9a75a2a
--- /dev/null
+++ b/tests/wpt/metadata/html/browsers/origin/cross-origin-objects/cross-origin-objects-on-new-window.html.ini
@@ -0,0 +1,2 @@
+[cross-origin-objects-on-new-window.html]
+  expected: TIMEOUT
diff --git a/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini b/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini
index 442db3cb549..2532dceabac 100644
--- a/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini
+++ b/tests/wpt/metadata/html/browsers/windows/embedded-opener-remove-frame.html.ini
@@ -1,4 +1,5 @@
 [embedded-opener-remove-frame.html]
+  expected: CRASH
   [opener and "removed" embedded documents]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini
index fc37df7e3fa..f42f518d257 100644
--- a/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-1.html.ini
@@ -1,6 +1,5 @@
 [iframe_sandbox_popups_escaping-1.html]
   type: testharness
-  expected: TIMEOUT
   [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-2.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_escaping-2.html.ini
index 4df5d7a35de..daa518bd0e3 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
@@ -1,4 +1,5 @@
 [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: 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 5f60c78e73c..f6a7aca3306 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
@@ -1,6 +1,5 @@
 [iframe_sandbox_popups_escaping-3.html]
   type: testharness
-  expected: TIMEOUT
   [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_nonescaping-1.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-iframe-element/iframe_sandbox_popups_nonescaping-1.html.ini
index 963d4cd20ef..9df1ac56f2a 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: CRASH
+  expected: TIMEOUT
   [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 dc856a3d5a3..e440b1e38c6 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
@@ -1,5 +1,6 @@
 [iframe_sandbox_popups_nonescaping-3.html]
   type: testharness
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe do not escape the sandbox]
-    expected: FAIL
+    expected: NOTRUN
 
diff --git a/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
new file mode 100644
index 00000000000..bcd2fd0eab8
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/scripting-1/the-script-element/execution-timing/077.html.ini
@@ -0,0 +1,4 @@
+[077.html]
+  [ adding several types of scripts through the DOM and removing some of them confuses scheduler ]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
deleted file mode 100644
index fca4d908c89..00000000000
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/document-write/module-static-import-delayed.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[module-static-import-delayed.html]
-  [document.write in an imported module]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
index 910c88d3e81..69bd952d756 100644
--- a/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
+++ b/tests/wpt/metadata/html/webappapis/dynamic-markup-insertion/opening-the-input-stream/ignore-opens-during-unload.window.js.ini
@@ -1,5 +1,5 @@
 [ignore-opens-during-unload.window.html]
-  expected: CRASH
+  expected: TIMEOUT
   [ignore-opens-during-unload]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini b/tests/wpt/metadata/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini
index 0cef5158fae..01f7b72cbe7 100644
--- a/tests/wpt/metadata/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini
+++ b/tests/wpt/metadata/html/webappapis/scripting/events/compile-event-handler-settings-objects.html.ini
@@ -4,3 +4,6 @@
   [The incumbent settings object while executing the compiled callback via Web IDL's invoke must be that of the node document]
     expected: TIMEOUT
 
+  [The entry settings object while executing the compiled callback via Web IDL's invoke must be that of the node document]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/wasm/jsapi/constructor/toStringTag.any.js.ini b/tests/wpt/metadata/wasm/jsapi/constructor/toStringTag.any.js.ini
new file mode 100644
index 00000000000..a5d04e20667
--- /dev/null
+++ b/tests/wpt/metadata/wasm/jsapi/constructor/toStringTag.any.js.ini
@@ -0,0 +1,21 @@
+[toStringTag.any.html]
+  [Object.prototype.toString applied after deleting @@toStringTag]
+    expected: FAIL
+
+  [@@toStringTag exists on the namespace object with the appropriate descriptor]
+    expected: FAIL
+
+  [Object.prototype.toString applied after modifying the namespace object's @@toStringTag]
+    expected: FAIL
+
+
+[toStringTag.any.worker.html]
+  [Object.prototype.toString applied after deleting @@toStringTag]
+    expected: FAIL
+
+  [@@toStringTag exists on the namespace object with the appropriate descriptor]
+    expected: FAIL
+
+  [Object.prototype.toString applied after modifying the namespace object's @@toStringTag]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/workers/constructors/Worker/Worker-constructor.html.ini b/tests/wpt/metadata/workers/constructors/Worker/Worker-constructor.html.ini
new file mode 100644
index 00000000000..80f9a4f15b8
--- /dev/null
+++ b/tests/wpt/metadata/workers/constructors/Worker/Worker-constructor.html.ini
@@ -0,0 +1,2 @@
+[Worker-constructor.html]
+  expected: ERROR
diff --git a/tests/wpt/web-platform-tests/.azure-pipelines.yml b/tests/wpt/web-platform-tests/.azure-pipelines.yml
index 215f3d8ffd8..cbd7b33b5d4 100644
--- a/tests/wpt/web-platform-tests/.azure-pipelines.yml
+++ b/tests/wpt/web-platform-tests/.azure-pipelines.yml
@@ -611,7 +611,7 @@ jobs:
   - template: tools/ci/azure/update_hosts.yml
   - template: tools/ci/azure/update_manifest.yml
   # --exclude is a workaround for https://github.com/web-platform-tests/wpt/issues/18995 + https://github.com/web-platform-tests/wpt/issues/20887 + https://github.com/web-platform-tests/wpt/issues/22175 + https://github.com/web-platform-tests/wpt/issues/23630
-  - script: ./wpt run --no-manifest-update --no-restart-on-unexpected --no-fail-on-unexpected --this-chunk=$(System.JobPositionInPhase) --total-chunks=$(System.TotalJobsInPhase) --chunk-type hash --log-wptreport $(Build.ArtifactStagingDirectory)/wpt_report_$(System.JobPositionInPhase).json --log-wptscreenshot $(Build.ArtifactStagingDirectory)/wpt_screenshot_$(System.JobPositionInPhase).txt --log-mach - --log-mach-level info safari --exclude /pointerevents/pointerevent_pointercapture-not-lost-in-chorded-buttons.html --exclude /pointerevents/pointerevent_pointercapture_in_frame.html --exclude /web-share/share-sharePromise-internal-slot.https.html --exclude /webdriver/tests/perform_actions/pointer_tripleclick.py
+  - script: ./wpt run --no-manifest-update --no-restart-on-unexpected --no-fail-on-unexpected --this-chunk=$(System.JobPositionInPhase) --total-chunks=$(System.TotalJobsInPhase) --chunk-type hash --log-wptreport $(Build.ArtifactStagingDirectory)/wpt_report_$(System.JobPositionInPhase).json --log-wptscreenshot $(Build.ArtifactStagingDirectory)/wpt_screenshot_$(System.JobPositionInPhase).txt --log-mach - --log-mach-level info --channel stable safari --exclude /pointerevents/pointerevent_pointercapture-not-lost-in-chorded-buttons.html --exclude /pointerevents/pointerevent_pointercapture_in_frame.html --exclude /web-share/share-sharePromise-internal-slot.https.html --exclude /webdriver/tests/perform_actions/pointer_tripleclick.py
     displayName: 'Run tests'
   - task: PublishBuildArtifacts@1
     displayName: 'Publish results'
diff --git a/tests/wpt/web-platform-tests/audio-output/setSinkId.https.html b/tests/wpt/web-platform-tests/audio-output/setSinkId.https.html
index b1f703a9350..80e2832e970 100644
--- a/tests/wpt/web-platform-tests/audio-output/setSinkId.https.html
+++ b/tests/wpt/web-platform-tests/audio-output/setSinkId.https.html
@@ -17,6 +17,8 @@ promise_test(t => promise_rejects_dom(t, "NotFoundError", audio.setSinkId("nonex
   "setSinkId fails with NotFoundError on made up deviceid");
 
 promise_test(async t => {
+  const stream = await navigator.mediaDevices.getUserMedia({audio:true});
+  stream.getAudioTracks()[0].stop();
   const list = await navigator.mediaDevices.enumerateDevices();
   const outputDevicesList = list.filter(({kind}) => kind == "audiooutput");
   assert_not_equals(outputDevicesList.length, 0,
diff --git a/tests/wpt/web-platform-tests/cookie-store/resources/cookie_helper.py b/tests/wpt/web-platform-tests/cookie-store/resources/cookie_helper.py
index cf48f26eed1..b88b25c7016 100755
--- a/tests/wpt/web-platform-tests/cookie-store/resources/cookie_helper.py
+++ b/tests/wpt/web-platform-tests/cookie-store/resources/cookie_helper.py
@@ -18,52 +18,76 @@
 #   Used to set cookies from an HTTP response header context.
 #
 # The response has 200 status and content-type: text/plain; charset=<charset>
-import cgi, encodings, os, re, sys, urllib
+import encodings, re
+
+from six import PY3
+
+from six.moves.urllib.parse import parse_qs, quote
+
+from wptserve.utils import isomorphic_decode, isomorphic_encode
 
 # NOTE: These are intentionally very lax to permit testing
-DISALLOWED_IN_COOKIE_NAME_RE = re.compile(r'[;\0-\x1f\x7f]');
-DISALLOWED_IN_HEADER_RE = re.compile(r'[\0-\x1f\x7f]');
+DISALLOWED_IN_COOKIE_NAME_RE = re.compile(br'[;\0-\x1f\x7f]')
+DISALLOWED_IN_HEADER_RE = re.compile(br'[\0-\x1f\x7f]')
 
 # Ensure common charset names do not end up with different
 # capitalization or punctuation
 CHARSET_OVERRIDES = {
     encodings.codecs.lookup(charset).name: charset
-    for charset in ('utf-8', 'iso-8859-1',)
+    for charset in (u'utf-8', u'iso-8859-1',)
 }
 
+def quote_str(cookie_str):
+  if PY3:
+    return isomorphic_encode(quote(isomorphic_decode(cookie_str), u'', encoding=u'iso-8859-1'))
+  else:
+    return quote(cookie_str, b'')
+
+def parse_qs_str(query_str):
+  if PY3:
+    args = parse_qs(isomorphic_decode(query_str), keep_blank_values=True, encoding=u'iso-8859-1')
+    binary_args = {}
+    for key, val in args.items():
+        binary_args[isomorphic_encode(key)] = [isomorphic_encode(x) for x in val]
+    return binary_args
+  else:
+    return parse_qs(query_str, keep_blank_values=True)
+
 def main(request, response):
   assert request.method in (
-      'GET',
-      'POST',
-  ), 'request method was neither GET nor POST: %r' % request.method
-  qd = (request.url.split('#')[0].split('?', 1) + [''])[1]
-  if request.method == 'POST':
-    qd += '&' + request.body
-  args = cgi.parse_qs(qd, keep_blank_values = True)
-  charset = encodings.codecs.lookup(args.get('charset', ['utf-8'])[-1]).name
+      u'GET',
+      u'POST',
+  ), u'request method was neither GET nor POST: %r' % request.method
+  qd = (isomorphic_encode(request.url).split(b'#')[0].split(b'?', 1) + [b''])[1]
+  if request.method == u'POST':
+    qd += b'&' + request.body
+  args = parse_qs_str(qd)
+
+  charset = encodings.codecs.lookup([isomorphic_decode(x) for x in args.get(b'charset', [u'utf-8'])][-1]).name
   charset = CHARSET_OVERRIDES.get(charset, charset)
-  headers = [('content-type', 'text/plain; charset=' + charset)]
+  headers = [(b'content-type', b'text/plain; charset=' + isomorphic_encode(charset))]
   body = []
-  if request.method == 'POST':
-    for set_cookie in args.get('set-cookie', []):
-      if '=' in set_cookie.split(';', 1)[0]:
-        name, rest = set_cookie.split('=', 1)
+  if request.method == u'POST':
+    for set_cookie in args.get(b'set-cookie', []):
+      if b'=' in set_cookie.split(b';', 1)[0]:
+        name, rest = set_cookie.split(b'=', 1)
         assert re.search(
             DISALLOWED_IN_COOKIE_NAME_RE,
             name
-        ) is None, 'name had disallowed characters: %r' % name
+        ) is None, b'name had disallowed characters: %r' % name
       else:
         rest = set_cookie
       assert re.search(
           DISALLOWED_IN_HEADER_RE,
           rest
-      ) is None, 'rest had disallowed characters: %r' % rest
-      headers.append(('set-cookie', set_cookie))
-      body.append('set-cookie=' + urllib.quote(set_cookie, ''))
+      ) is None, b'rest had disallowed characters: %r' % rest
+      headers.append((b'set-cookie', set_cookie))
+      body.append(b'set-cookie=' + quote_str(set_cookie))
+
   else:
-    cookie = request.headers.get('cookie')
+    cookie = request.headers.get(b'cookie')
     if cookie is not None:
-      body.append('cookie=' + urllib.quote(cookie, ''))
-  body = '\r\n'.join(body)
-  headers.append(('content-length', str(len(body))))
+      body.append(b'cookie=' + quote_str(cookie))
+  body = b'\r\n'.join(body)
+  headers.append((b'content-length', len(body)))
   return 200, headers, body
diff --git a/tests/wpt/web-platform-tests/css/css-backgrounds/background-attachment-353.html b/tests/wpt/web-platform-tests/css/css-backgrounds/background-attachment-353.html
new file mode 100644
index 00000000000..c5ac06c0f57
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-backgrounds/background-attachment-353.html
@@ -0,0 +1,131 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Background and Borders Test: 'background-attachment: local' and 'overflow: hidden'</title>
+
+  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">
+  <link rel="help" href="http://www.w3.org/TR/css3-background/#the-background-attachment">
+  <link rel="match" href="../reference/ref-filled-green-100px-square.xht">
+  <link rel="stylesheet" type="text/css" href="/fonts/ahem.css">
+
+  <!--
+
+  More info:
+
+  Re: [css3-background] background-attachment: local
+  http://lists.w3.org/Archives/Public/www-style/2013May/0542.html
+
+  -->
+
+  <meta content="" name="flags">
+  <meta content="This test checks that when an element has 'background-attachment: local', then the background image is fixed with regard to what is the element's scrollable area and not to its viewport. In this test, what would be the scrollable area for the div#target element is where the red area of its background image 100x100-gr-rr.png is and such area is clipped due to 'overflow: hidden'." name="assert">
+
+  <style>
+  div#control
+    {
+      background-color: red;
+      border: solid green;
+      border-width: 50px 0 0 50px;
+      height: 50px;
+      margin-bottom: -100px;
+      width: 50px;
+    }
+
+  div#target
+    {
+      background-attachment: local;
+      background-image: url("support/100x100-gr-rr.png");
+      background-repeat: no-repeat;
+      background-position: center;
+      font-family: Ahem;
+      font-size: 100px;
+      line-height: 1;
+      height: 100px;
+      overflow: hidden;
+      width: 100px;
+    }
+  </style>
+
+  <body>
+
+  <p>Test passes if there is a filled green square and <strong>no red</strong>.
+
+  <div id="control"></div>
+
+  <div id="target">&nbsp;&nbsp;<br>&nbsp;&nbsp;</div>
+
+  <!--
+
+  div#control is
+
+  (0px, 0px)              (100px, 0px)
+  +.......................+
+  |                       |
+  |                       |
+  |     green  area       |
+  |                       |
+  |                       |
+  |     green  area       |
+  |                       |
+  |             +........+|
+  |   green     |  red   ||
+  |    area     | area   ||
+  |             |        ||
+  |             +........+|
+  +.......................+
+(0px, 100px)            (100px, 100px)
+
+
+  =   =   =   =   =   =   =
+
+
+  div#target with background-position: top left
+
+  (0px, 0px)              (100px, 0px)
+  +.......................+
+  | +........+            |
+  | | green  |    red     |
+  | |  area  |    area    |
+  | |        |            |
+  | +........+            |
+  |                       |
+  |      red  area        |
+  |                       |
+  |                       |
+  |      red  area        |
+  |                       |
+  |                       |
+  +.......................+
+(0px, 100px)            (100px, 100px)
+
+
+  =   =   =   =   =   =   =
+
+
+  div#target with background-position: center
+
+  (0px, 0px)              (100px, 0px)
+  +.......................+
+  |                       |
+  |  transparent  area    |
+  |                       |   overflowed
+  |                       |      area
+  |  transparent  area    |        |
+  |                       |        V
+  |           +...........| ...........+
+  |           | +........+|             |
+  |  transpa- | |  green ||     red     |
+  |  rent     | |  area  ||    area     |
+  |  area     | |        ||             |
+  |           | +........+|             |
+  +.......................+             |
+              |                         |
+              |        red  area        |   <--  overflowed
+              |                         |   <--     area
+              |        red  area        |
+              |                         |
+              |                         |
+              +.........................+
+
+  -->
diff --git a/tests/wpt/web-platform-tests/css/css-backgrounds/support/100x100-gr-rr.png b/tests/wpt/web-platform-tests/css/css-backgrounds/support/100x100-gr-rr.png
new file mode 100644
index 00000000000..dfd0593e3c4
Binary files /dev/null and b/tests/wpt/web-platform-tests/css/css-backgrounds/support/100x100-gr-rr.png differ
diff --git a/tests/wpt/web-platform-tests/css/css-flexbox/grid-flex-item-005.html b/tests/wpt/web-platform-tests/css/css-flexbox/grid-flex-item-005.html
new file mode 100644
index 00000000000..95c57d1429e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-flexbox/grid-flex-item-005.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<link rel="help" href="https://crbug.com/1108928">
+<link rel="match" href="../reference/ref-filled-green-100px-square-only.html">
+<p>Test passes if there is a filled green square.</p>
+<div id="target">
+  <div style="display: flex; flex-direction: column">
+    <div style="display: grid; height: 0; flex: 1; grid-template-rows: minmax(100px, 200%);">
+      <div style="background: green;"></div>
+    </div>
+  </div>
+</div>
+<script>
+document.body.offsetTop;
+document.getElementById('target').style.width = '100px';
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-grid/alignment/grid-place-content-001.html b/tests/wpt/web-platform-tests/css/css-grid/alignment/grid-place-content-001.html
new file mode 100644
index 00000000000..49bb63928be
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-grid/alignment/grid-place-content-001.html
@@ -0,0 +1,139 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Grid Layout Test: Grid containers support 'place-content'</title>
+<link rel="author" title="Oriol Brufau" href="mailto:obrufau@igalia.com">
+<link rel="help" href="https://drafts.csswg.org/css-grid-1/#grid-align" title="10.5. Aligning the Grid: the 'justify-content' and 'align-content' properties">
+<link rel="help" href="https://drafts.csswg.org/css-align-3/#align-justify-content" title="5.1. The 'justify-content' and 'align-content' Properties">
+<meta name="assert" content="This test checks that the 'justify-content' and 'align-content' properties, set using their 'place-content' shorthand, work well in grid containers.">
+<link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
+<style>
+.grid {
+  display: inline-grid;
+  position: relative;
+  vertical-align: top;
+  border: 10px solid black;
+  margin: 5px;
+  font: 40px/1 Ahem;
+  color: cyan;
+}
+.small {
+  padding: 40px;
+}
+.big {
+  padding: 0px;
+}
+.content-box.small {
+  width: 0px;
+  height: 0px;
+}
+.content-box.big {
+  width: 80px;
+  height: 80px;
+}
+.border-box {
+  box-sizing: border-box;
+  width: 100px;
+  height: 100px;
+}
+.start {
+  place-content: start;
+}
+.center {
+  place-content: center;
+}
+.end {
+  place-content: end;
+}
+.space-between {
+  place-content: space-between;
+}
+.space-around {
+  place-content: space-around;
+}
+</style>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/check-layout-th.js"></script>
+<div id="log"></div>
+
+<h3>Small content area</h3>
+
+<pre>box-sizing: content-box</pre>
+
+<div class="grid small content-box start">
+  <div data-offset-x="40" data-offset-y="40">X</div>
+</div>
+<div class="grid small content-box center">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+<div class="grid small content-box end">
+  <div data-offset-x="0" data-offset-y="0">X</div>
+</div>
+<div class="grid small content-box space-between">
+  <div data-offset-x="40" data-offset-y="40">X</div>
+</div>
+<div class="grid small content-box space-around">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+
+<pre>box-sizing: border-box</pre>
+
+<div class="grid small border-box start">
+  <div data-offset-x="40" data-offset-y="40">X</div>
+</div>
+<div class="grid small border-box center">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+<div class="grid small border-box end">
+  <div data-offset-x="0" data-offset-y="0">X</div>
+</div>
+<div class="grid small border-box space-between">
+  <div data-offset-x="40" data-offset-y="40">X</div>
+</div>
+<div class="grid small border-box space-around">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+
+<h3>Big content area</h3>
+
+<pre>box-sizing: content-box</pre>
+
+<div class="grid big content-box start">
+  <div data-offset-x="0" data-offset-y="0">X</div>
+</div>
+<div class="grid big content-box center">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+<div class="grid big content-box end">
+  <div data-offset-x="40" data-offset-y="40">X</div>
+</div>
+<div class="grid big content-box space-between">
+  <div data-offset-x="0" data-offset-y="0">X</div>
+</div>
+<div class="grid big content-box space-around">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+
+<pre>box-sizing: border-box</pre>
+
+<div class="grid border-box start">
+  <div data-offset-x="0" data-offset-y="0">X</div>
+</div>
+<div class="grid big border-box center">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+<div class="grid big border-box end">
+  <div data-offset-x="40" data-offset-y="40">X</div>
+</div>
+<div class="grid big border-box space-between">
+  <div data-offset-x="0" data-offset-y="0">X</div>
+</div>
+<div class="grid big border-box space-around">
+  <div data-offset-x="20" data-offset-y="20">X</div>
+</div>
+
+<script>
+document.fonts.ready.then(() => {
+  checkLayout('.grid');
+});
+</script>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-001-manual.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-001-manual.html
new file mode 100644
index 00000000000..55001fe379f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-001-manual.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and color (basic)</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="interact" name="flags">
+
+  <style>
+  div
+    {
+      color: red;
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      color: green;
+    }
+  </style>
+
+  <p>Instructions: Select a few or all characters from the words "Text sample" using a variety of methods:
+
+  <ul>
+    <li>Select by dragging (leftwardedly or rightwardedly) the mouse across the characters.
+    <li>Select by using shift + keyboard arrows when keyboard navigation / caret browsing is enabled.
+    <li>Double click a word to select it.
+    <li>Triple click the text to select it.
+  </ul>
+
+  <p>Test passes if, in every case, the selected characters become green <em>and</em> if there is no background color for the characters selection.
+
+  <div>Text sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-002-manual.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-002-manual.html
new file mode 100644
index 00000000000..01cec72b2d4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-002-manual.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and background-color (basic)</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="interact" name="flags">
+
+  <style>
+  div
+    {
+      background-color: red;
+      color: aqua;
+      display: inline;
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      background-color: green;
+    }
+
+  /*
+  Chromium 77.0.3855.0 creates a background-color #334C00 or rgb(51, 76, 0)
+  and not a green (#008000 or rgb(0, 128, 0)) background color.
+
+  Issue 1018450: background-color of ::selection should be painted as specified
+  https://bugs.chromium.org/p/chromium/issues/detail?id=1018450
+  */
+  </style>
+
+  <p>Instructions: Select a few or all characters from the words "Text sample" using a variety of methods:
+
+  <ul>
+    <li>Select by dragging (leftwardedly or rightwardedly) the mouse across the characters.
+    <li>Select by using shift + keyboard arrows when keyboard navigation / caret browsing is enabled.
+    <li>Double click a word to select it.
+    <li>Triple click the text to select it.
+  </ul>
+
+  <p>Test passes if, in every case, the background color of selected characters become green <em>and</em> if text color of selected characters remains aqua.
+
+  <div>Text sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-003-manual.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-003-manual.html
new file mode 100644
index 00000000000..c56a301ef3a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-003-manual.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and cursor (basic)</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="interact should" name="flags">
+
+  <style>
+  div
+    {
+      cursor: auto;
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      cursor: url("support/select-custom.cur"), help;
+    }
+
+  img
+    {
+      vertical-align: -1em;
+    }
+  </style>
+
+  <p>Instructions: Select a few or all characters from the words "Text sample" using a variety of methods:
+
+  <ul>
+    <li>Select by dragging (leftwardedly or rightwardedly) the mouse across the characters.
+    <li>Select by using shift + keyboard arrows when keyboard navigation / caret browsing is enabled.
+    <li>Double click a word to select it.
+    <li>Triple click the text to select it.
+  </ul>
+
+  <p>Test passes if, in every case, the cursor becomes <img src="support/select-custom.png" width="32" height="32" alt="Image download support must be enabled"> when hovering anywhere over the selection of "Text sample" <em>and</em> if the background color and color of the selected text are the same as when selecting text from these instructions.
+
+  <div>Text sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-004-manual.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-004-manual.html
new file mode 100644
index 00000000000..ac7ba7da327
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-004-manual.html
@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and text-decoration (basic)</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="interact should" name="flags">
+
+  <style>
+  div
+    {
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      text-decoration: fuchsia underline dotted;
+    }
+  </style>
+
+  <p>Instructions: Select a few or all characters from the words "Text sample" using a variety of methods:
+
+  <ul>
+    <li>Select by dragging (leftwardedly or rightwardedly) the mouse across the characters.
+    <li>Select by using shift + keyboard arrows when keyboard navigation / caret browsing is enabled.
+    <li>Double click a word to select it.
+    <li>Triple click the text to select it.
+  </ul>
+
+  <p>Test passes if, in every case, the selected glyphs of "Text sample" are underlined with a fuchsia dotted line <em>and</em> if the background color and color of the selected text are the same as when selecting text from these instructions.
+
+  <div>Text sample</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-011.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-011.html
new file mode 100644
index 00000000000..57335dc52d9
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-011.html
@@ -0,0 +1,43 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and color (basic)</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">
+  <link rel="match" href="reference/active-selection-011-ref.html">
+
+  <meta content="" name="flags">
+
+  <style>
+  div
+    {
+      color: red;
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      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 each glyph of "Selected Text" is green and <strong>not red</strong> while background color of each glyph of "Selected Text" is white.
+
+  <div id="test">Selected Text</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-012.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-012.html
new file mode 100644
index 00000000000..e40b0d2a0d2
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-012.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and background-color (basic)</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">
+  <link rel="match" href="reference/active-selection-012-ref.html">
+
+  <meta content="" name="flags">
+
+  <style>
+  div
+    {
+      background-color: red;
+      color: fuchsia;
+      display: inline;
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      background-color: green;
+    }
+
+  /*
+  Chromium 77.0.3855.0 and above create a background-color #334C00 or
+  rgb(51, 76, 0) and not a green (#008000 or rgb(0, 128, 0)) background
+  color.
+  */
+  </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 the background color of each glyph of "Selected Text" is green and <strong>not red</strong> while each glyph of "Selected Text" is fuchsia.
+
+  <div id="test">Selected Text</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-014.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-014.html
new file mode 100644
index 00000000000..1bc244c800a
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-014.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection and text-decoration</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">
+  <link rel="help" href="https://www.w3.org/TR/css-pseudo-4/#highlight-painting">
+  <link rel="match" href="reference/active-selection-014-ref.html">
+
+  <meta content="should" name="flags">
+  <meta name="assert" content="This test checks that 'text-decoration' applies to highlight pseudo-element. Since neither 'color' nor 'background-color' has been specified by the pseudo-element selector in this test, then OS-default highlight colors should be used. The consequence of this is that the highlight color determines also the color of the underline.">
+
+  <style>
+  div
+    {
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      text-decoration: underline;
+    }
+  </style>
+
+  <!--
+  "
+  The element's own text decorations (both line decorations
+  and emphasis marks) are thus drawn in the pseudo-element's
+  own color when that is not currentColor, regardless of
+  their original color or fill specifications.
+  "
+  coming from
+  https://www.w3.org/TR/css-pseudo-4/#highlight-painting
+  -->
+
+  <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 each glyph of "Selected Text" is underlined and if color and background color of "Selected Text" are the OS-default highlight colors. The underline color must also be the same as the highlight color of "Selected Text".
+
+  <div id="test">Selected Text</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-016.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-016.html
new file mode 100644
index 00000000000..e5a56afe022
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-016.html
@@ -0,0 +1,46 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection of partial text and color</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">
+  <link rel="match" href="reference/active-selection-016-ref.html">
+
+  <meta content="" name="flags">
+
+  <style>
+  div
+    {
+      background-color: white;
+      color: white;
+      font-size: 300%;
+    }
+
+  div::selection
+    {
+      color: green;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.setStart(document.getElementById("test").childNodes[0], 5);
+  /*
+  Then we set the start boundary of the range inside div#test to
+  */
+  targetRange.setEnd(document.getElementById("test").childNodes[0], 9);
+  /* And we set the end boundary of the range inside div#test right */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <div id="test">FAIL PASS FAIL</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-018.html b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-018.html
new file mode 100644
index 00000000000..ee7871c9503
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/active-selection-018.html
@@ -0,0 +1,60 @@
+<!DOCTYPE html>
+
+  <meta charset="UTF-8">
+
+  <title>CSS Pseudo-Elements Test: active selection, color and background-color</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">
+  <link rel="match" href="reference/active-selection-011-ref.html">
+
+  <meta content="" name="flags">
+
+  <style>
+  div
+    {
+      color: green;
+      font-size: 300%;
+    }
+
+  span
+    {
+      color: red;
+    }
+
+  div::selection
+    {
+      background-color: white;
+    }
+  /*
+  This div::selection rule is necessary. Without it,
+  "Selected Text" would be using the OS-default
+  highlight colors for ::selection
+  because neither color nor background-color would have
+  been specified by the author.
+  */
+
+  span::selection
+    {
+      color: white;
+    }
+  </style>
+
+  <script>
+  function startTest()
+  {
+  var targetRange = document.createRange();
+  /* We first create an empty range */
+  targetRange.selectNodeContents(document.getElementById("parent"));
+  /* Then we set the range boundaries to the children of div#parent */
+  window.getSelection().addRange(targetRange);
+  /* Finally, we now select such range of content */
+  }
+  </script>
+
+  <body onload="startTest();">
+
+  <p>Test passes if each glyph of "Selected Text" is green and if there is <strong>no red</strong>.
+
+  <div id="parent">Selected Text <span>FAIL</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-011-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-011-ref.html
new file mode 100644
index 00000000000..5c5fb091b85
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-011-ref.html
@@ -0,0 +1,19 @@
+<!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
+    {
+      color: green;
+      font-size: 300%;
+    }
+  </style>
+
+  <p>Test passes if each glyph of "Selected Text" is green and <strong>not red</strong> while background color of each glyph of "Selected Text" is white.
+
+  <div>Selected Text</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-012-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-012-ref.html
new file mode 100644
index 00000000000..2faa69510d8
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-012-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: fuchsia;
+      display: inline;
+      font-size: 300%;
+    }
+  </style>
+
+  <p>Test passes if the background color of each glyph of "Selected Text" is green and <strong>not red</strong> while each glyph of "Selected Text" is fuchsia.
+
+  <div>Selected Text</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-014-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-014-ref.html
new file mode 100644
index 00000000000..4a9dd309a01
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-014-ref.html
@@ -0,0 +1,47 @@
+<!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: Highlight;
+      color: HighlightText;
+      display: inline;
+      font-size: 300%;
+      text-decoration: HighlightText underline;
+    }
+  </style>
+
+  <!--
+  "
+  The element's own text decorations (both line decorations
+  and emphasis marks) are thus drawn in the pseudo-element's
+  own color when that is not currentColor, regardless of
+  their original color or fill specifications.
+  "
+  coming from
+  https://www.w3.org/TR/css-pseudo-4/#highlight-painting
+
+  Highlight
+      Background of item(s) selected in a control.
+  https://www.w3.org/TR/css-color-4/#valdef-system-color-highlight
+
+  HighlightText
+      Text of item(s) selected in a control.
+  https://www.w3.org/TR/css-color-4/#valdef-system-color-highlighttext
+
+  CSS4 Color Module
+  5.2 System Colors
+  https://www.w3.org/TR/css-color-4/#css-system-colors
+  -->
+
+  <body>
+
+  <p>Test passes if each glyph of "Selected Text" is underlined and if color and background color of "Selected Text" are the OS-default highlight colors. The underline color must also be the same as the highlight color of "Selected Text".
+
+  <div id="test">Selected Text</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-016-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-016-ref.html
new file mode 100644
index 00000000000..cd80adb3c3b
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/reference/active-selection-016-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
+    {
+      color: white;
+      font-size: 300%;
+    }
+
+  span
+    {
+      color: green;
+    }
+  </style>
+
+  <div>FAIL <span>PASS</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-011-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-011-ref.html
index b0c60408f76..b3fa3531b3e 100644
--- a/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-011-ref.html
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-011-ref.html
@@ -9,13 +9,16 @@
   <style>
   div
     {
-      background-color: yellow;
-      display: inline-block;
       font-size: 48px;
       letter-spacing: 1em;
     }
 
-  span
+  span#yellow
+    {
+      background-color: yellow;
+    }
+
+  span#orange
     {
       background-color: orange;
     }
@@ -23,4 +26,4 @@
 
   <p>Test passes if the background of characters "c" and "t" is orange (and only those 2 characters) and if the space between those 2 characters is also orange.
 
-  <div>Sele<span>ct</span>ed Text</div>
+  <div><span id="yellow">Sele<span id="orange">ct</span>ed</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-012-ref.html b/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-012-ref.html
index 38650c90b40..3ead305bfb8 100644
--- a/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-012-ref.html
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/reference/selection-intercharacter-012-ref.html
@@ -9,13 +9,16 @@
   <style>
   div
     {
-      background-color: yellow;
-      display: inline-block;
       font-size: 48px;
       letter-spacing: 1em;
     }
 
-  span
+  span#yellow
+    {
+      background-color: yellow;
+    }
+
+  span.orange
     {
       background-color: orange;
     }
@@ -23,4 +26,4 @@
 
   <p>Test passes if the background of characters "c" and "t" is orange and if the space between those 2 characters is yellow (and not orange).
 
-  <div>Sele<span>c</span> <span>t</span>ed Text</div>
+  <div><span id="yellow">Sele<span class="orange">c</span> <span class="orange">t</span>ed</span></div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-011.html b/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-011.html
index 70ab69fb492..a8f02b10e0f 100644
--- a/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-011.html
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-011.html
@@ -46,4 +46,4 @@
 
   <p>Test passes if the background of characters "c" and "t" is orange (and only those 2 characters) and if the space between those 2 characters is also orange.
 
-  <div id="test">Sele<span>ct</span>ed Text</div>
+  <div id="test">Sele<span>ct</span>ed</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-012.html b/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-012.html
index a04fc33e2fe..8dc665b77c9 100644
--- a/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-012.html
+++ b/tests/wpt/web-platform-tests/css/css-pseudo/selection-intercharacter-012.html
@@ -46,4 +46,4 @@
 
   <p>Test passes if the background of characters "c" and "t" is orange and if the space between those 2 characters is yellow (and not orange).
 
-  <div id="test">Sele<span>c</span> <span>t</span>ed Text</div>
+  <div id="test">Sele<span>c</span> <span>t</span>ed</div>
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/support/select-custom.cur b/tests/wpt/web-platform-tests/css/css-pseudo/support/select-custom.cur
new file mode 100644
index 00000000000..0a1f5dd5145
Binary files /dev/null and b/tests/wpt/web-platform-tests/css/css-pseudo/support/select-custom.cur differ
diff --git a/tests/wpt/web-platform-tests/css/css-pseudo/support/select-custom.png b/tests/wpt/web-platform-tests/css/css-pseudo/support/select-custom.png
new file mode 100644
index 00000000000..344aacee6af
Binary files /dev/null and b/tests/wpt/web-platform-tests/css/css-pseudo/support/select-custom.png differ
diff --git a/tests/wpt/web-platform-tests/css/cssom-view/client-props-root.html b/tests/wpt/web-platform-tests/css/cssom-view/client-props-root.html
new file mode 100644
index 00000000000..875522ec7c1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/cssom-view/client-props-root.html
@@ -0,0 +1,29 @@
+<!doctype html>
+<title>client* on the scrolling element</title>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width">
+<link rel="help" href="https://drafts.csswg.org/cssom-view/#extension-to-the-element-interface">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1654769">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<style>
+  :root {
+    /* Ensure the width of the root element's box is smaller than the viewport. */
+    margin: 5px;
+    /* Remove the scrollbars so that we can test {Width, Height}. */
+    scrollbar-width: none;
+    /* Would love to add a border but https://github.com/w3c/csswg-drafts/issues/5363 */
+  }
+</style>
+<div style="height: 200vh; width: 200vw"></div>
+<script>
+test(function() {
+  scrollTo(100, 100);
+  assert_equals(document.documentElement.clientTop, 0, "Client top doesn't depend on scrolling");
+  assert_equals(document.documentElement.clientLeft, 0, "Client left doesn't depend on scrolling");
+  assert_equals(document.documentElement.clientWidth, window.innerWidth, "Without scrollbars, client width should match viewport width");
+  assert_equals(document.documentElement.clientHeight, window.innerHeight, "Without scrollbars, client height should match viewport height");
+}, "client* properties on the root element");
+</script>
diff --git a/tests/wpt/web-platform-tests/fetch/range/resources/long-wav.py b/tests/wpt/web-platform-tests/fetch/range/resources/long-wav.py
index 8af2aca8a95..be7df7b83d8 100644
--- a/tests/wpt/web-platform-tests/fetch/range/resources/long-wav.py
+++ b/tests/wpt/web-platform-tests/fetch/range/resources/long-wav.py
@@ -118,12 +118,11 @@ def main(request, response):
     bytes_remaining_to_send -= len(initial_write)
 
     while bytes_remaining_to_send > 0:
-        if not response.writer.flush():
-            break
-
         to_send = b'\x00' * min(bytes_remaining_to_send, sample_rate)
         bytes_remaining_to_send -= len(to_send)
 
-        response.writer.write(to_send)
+        if not response.writer.write(to_send):
+            break
+
         # Throttle the stream
         time.sleep(0.5)
diff --git a/tests/wpt/web-platform-tests/focus/focus-restoration-in-different-site-iframes.html b/tests/wpt/web-platform-tests/focus/focus-restoration-in-different-site-iframes.html
new file mode 100644
index 00000000000..3de05455651
--- /dev/null
+++ b/tests/wpt/web-platform-tests/focus/focus-restoration-in-different-site-iframes.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>Test focus restoration</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script>
+setup({explicit_done:true});
+window.onmessage = function(e) {
+    test(function() {
+        assert_equals(e.data, "outerlog:log:bodyfocus,inputfocus,inputblur,bodyblur,bodyfocus,inputfocus,", 'Check log');
+    }, "Check result");
+    w.close();
+    done();
+};
+var w = window.open("support/focus-restoration-in-different-site-iframes-outer.sub.html");
+</script>
diff --git a/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-inner.html b/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-inner.html
new file mode 100644
index 00000000000..903b0c02858
--- /dev/null
+++ b/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-inner.html
@@ -0,0 +1,37 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8">
+    <title>Inner document</title>
+</head>
+<body>
+<h1>Inner</h1>
+<input type="text">
+<script>
+window.onmessage = function(e) {
+    if (e.data == "getlog") {
+        parent.postMessage(log, "*");
+    }
+};
+
+let log = "log:";
+let input = document.getElementsByTagName("input")[0];
+input.onfocus = function() {
+    log += "inputfocus,"
+}
+input.onblur = function() {
+    log += "inputblur,"
+}
+document.body.onfocus = function() {
+    log += "bodyfocus,"
+}
+document.body.onblur = function() {
+    log += "bodyblur,"
+}
+window.onload = function() {
+    input.focus();
+    parent.postMessage("start", "*");
+}
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-other.html b/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-other.html
new file mode 100644
index 00000000000..b302b909387
--- /dev/null
+++ b/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-other.html
@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<script>
+window.onload = function() {
+    opener.postMessage("other", "*");
+}
+</script>
diff --git a/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-outer.sub.html b/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-outer.sub.html
new file mode 100644
index 00000000000..91ffed11075
--- /dev/null
+++ b/tests/wpt/web-platform-tests/focus/support/focus-restoration-in-different-site-iframes-outer.sub.html
@@ -0,0 +1,39 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>Focus restoration outer</title>
+<script>
+let other = null;
+let log = "outerlog:";
+function getLog() {
+    return log;
+}
+window.onmessage = function(e) {
+    if (e.data == "start") {
+        other = window.open("focus-restoration-in-different-site-iframes-other.html", "otherwindow", "resizable=yes");
+    } else if (e.data == "other") {
+        other.close();
+        setTimeout(function() {
+            document.getElementsByTagName("iframe")[0].contentWindow.postMessage("getlog", "*");
+        }, 2000);
+    } else {
+        setTimeout(function() {
+            opener.postMessage(getLog() + e.data, "*");
+        }, 1000);
+    }
+};
+window.onload = function() {
+    document.getElementsByTagName("iframe")[0].onfocus = function() {
+        log += "iframefocus,";
+    }
+    document.getElementsByTagName("iframe")[0].onblur = function() {
+        log += "iframeblur,";
+    }
+    document.body.onfocus = function() {
+        log += "bodyfocus,";
+    }
+    document.body.onblur = function() {
+        log += "bodyblur,";
+    }
+}
+</script>
+<iframe src="http://{{hosts[alt][www]}}:{{ports[http][0]}}/focus/support/focus-restoration-in-different-site-iframes-inner.html">
diff --git a/tests/wpt/web-platform-tests/html/browsers/the-window-object/window-open-invalid-url.html b/tests/wpt/web-platform-tests/html/browsers/the-window-object/window-open-invalid-url.html
new file mode 100644
index 00000000000..cabc143b9db
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/browsers/the-window-object/window-open-invalid-url.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>window.open() with an invalid URL</title>
+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<script>
+test(() => {
+  assert_throws_dom("SyntaxError", () => window.open("https://example.com\u0000mozilla.org"));
+}, "Window.open should throw SyntaxError when an invalid url is passed as the first parameter");
+</script>
diff --git a/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/access-reporting/property.https.html b/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/access-reporting/property.https.html
index 67aebb5838b..625fc941177 100644
--- a/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/access-reporting/property.https.html
+++ b/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/access-reporting/property.https.html
@@ -23,12 +23,10 @@ let property= [
   ["focus"       , w => w.focus()            ] ,
   ["frames"      , w => w.frames             ] ,
   ["indexed"     , w => w[0]                 ] ,
-  ["indexed"     , w => w[0] = ""            ] ,
   ["length"      , w => w.length             ] ,
   ["location"    , w => w.location           ] ,
   ["location"    , w => w.location = "#"     ] ,
   ["named"       , w => w["test"]            ] ,
-  ["named"       , w => w["test"] = ""       ] ,
   ["opener"      , w => w.opener             ] ,
   ["opener"      , w => w.opener = ""        ] ,
   ["postMessage" , w => w.postMessage("")    ] ,
diff --git a/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/resources/dispatcher.py b/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/resources/dispatcher.py
index 2f1cf1bd4cf..2617361b0b3 100644
--- a/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/resources/dispatcher.py
+++ b/tests/wpt/web-platform-tests/html/cross-origin-opener-policy/reporting/resources/dispatcher.py
@@ -9,17 +9,12 @@ def main(request, response):
         return b''
 
     uuid = request.GET[b'uuid']
-    stashed = request.server.stash.take(uuid)
-    if stashed is None:
-        stashed = []
 
     if request.method == u'POST':
-        stashed.append(request.body)
-        ret = b'done'
+        return request.server.stash.put(uuid, request.body)
     else:
-        if len(stashed) == 0:
-            ret = b'not ready'
+        body = request.server.stash.take(uuid)
+        if body is None:
+            return b'not ready'
         else:
-            ret = stashed.pop(0)
-    request.server.stash.put(uuid, stashed)
-    return ret;
+            return body
diff --git a/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-iframe-element/support/download_stash.py b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-iframe-element/support/download_stash.py
index 95256a2457a..a95fe37dd88 100644
--- a/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-iframe-element/support/download_stash.py
+++ b/tests/wpt/web-platform-tests/html/semantics/embedded-content/the-iframe-element/support/download_stash.py
@@ -22,7 +22,6 @@ def main(request, response):
     single_delay = finish_delay / count
     for i in range(count): # pylint: disable=unused-variable
         time.sleep(single_delay)
-        response.writer.write_content(u"\n")
-        if not response.writer.flush():
+        if not response.writer.write_content(b"\n"):
           return
     request.server.stash.put(token, True)
diff --git a/tests/wpt/web-platform-tests/interfaces/geolocation-API.idl b/tests/wpt/web-platform-tests/interfaces/geolocation-API.idl
index e8dd1526fd0..8bce6413816 100644
--- a/tests/wpt/web-platform-tests/interfaces/geolocation-API.idl
+++ b/tests/wpt/web-platform-tests/interfaces/geolocation-API.idl
@@ -14,8 +14,8 @@ interface Geolocation {
                           optional PositionOptions options = {});
 
   long watchPosition(PositionCallback successCallback,
-                     optional PositionErrorCallback errorCallback,
-                     optional PositionOptions options = {});
+                      optional PositionErrorCallback errorCallback,
+                      optional PositionOptions options = {});
 
   void clearWatch(long watchId);
 };
diff --git a/tests/wpt/web-platform-tests/layout-instability/move-transformed.html b/tests/wpt/web-platform-tests/layout-instability/move-transformed.html
new file mode 100644
index 00000000000..c9cdb9954b7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/layout-instability/move-transformed.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<title>Layout Instability: shift of a transformed container</title>
+<link rel="help" href="https://wicg.github.io/layout-instability/" />
+<style>
+body { margin: 0; }
+#transformed { position: relative; transform: translateX(20px); width: 100px; height: 100px; }
+</style>
+<div id="transformed"></div>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/util.js"></script>
+<script>
+
+promise_test(async () => {
+  const watcher = new ScoreWatcher;
+
+  // Wait for the initial render to complete.
+  await waitForAnimationFrames(2);
+
+  document.querySelector("#transformed").style = "top: 50px";
+
+  const expectedScore = computeExpectedScore(100 * (100 + 50), 50);
+
+  await watcher.promise;
+  assert_equals(watcher.score, expectedScore);
+}, 'Move transformed container');
+
+</script>
diff --git a/tests/wpt/web-platform-tests/layout-instability/transform-change.html b/tests/wpt/web-platform-tests/layout-instability/transform-change.html
new file mode 100644
index 00000000000..fd9657a7145
--- /dev/null
+++ b/tests/wpt/web-platform-tests/layout-instability/transform-change.html
@@ -0,0 +1,33 @@
+<!DOCTYPE html>
+<title>Layout Instability: transform change</title>
+<link rel="help" href="https://wicg.github.io/layout-instability/" />
+<style>
+body { margin: 0; }
+#transformed { position: relative; transform: translateX(20px); width: 100px; height: 100px; }
+#child { width: 400px; height: 400px; }
+</style>
+<div id="transformed">
+  <div id="child"></div>
+</div>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="resources/util.js"></script>
+<script>
+
+promise_test(async () => {
+  const watcher = new ScoreWatcher;
+
+  // Wait for the initial render to complete.
+  await waitForAnimationFrames(2);
+
+  // Modify the transform, for which no shift should be reported.
+  document.querySelector("#transformed").style = "transform: translateY(100px)";
+  // Change size of child, for which no shift should be reported, either.
+  document.querySelector("#child").style = "width: 300px";
+
+  await waitForAnimationFrames(2);
+  // No shift should be reported.
+  assert_equals(watcher.score, 0);
+}, 'transform change');
+
+</script>
diff --git a/tests/wpt/web-platform-tests/lint.ignore b/tests/wpt/web-platform-tests/lint.ignore
index 40b7cb2c218..e52c2ae4576 100644
--- a/tests/wpt/web-platform-tests/lint.ignore
+++ b/tests/wpt/web-platform-tests/lint.ignore
@@ -217,6 +217,7 @@ SET TIMEOUT: webvtt/*
 SET TIMEOUT: workers/*
 SET TIMEOUT: xhr/resources/init.htm
 SET TIMEOUT: xhr/resources/xmlhttprequest-timeout.js
+SET TIMEOUT: focus/support/focus-restoration-in-different-site-iframes-outer.sub.html
 
 # generate_tests implementation and sample usage
 GENERATE_TESTS: resources/test/tests/functional/generate-callback.html
diff --git a/tests/wpt/web-platform-tests/mediacapture-streams/MediaDevices-getUserMedia.https.html b/tests/wpt/web-platform-tests/mediacapture-streams/MediaDevices-getUserMedia.https.html
index 693f3bd11cf..f410b262cf5 100644
--- a/tests/wpt/web-platform-tests/mediacapture-streams/MediaDevices-getUserMedia.https.html
+++ b/tests/wpt/web-platform-tests/mediacapture-streams/MediaDevices-getUserMedia.https.html
@@ -40,6 +40,8 @@ test(function () {
 promise_test(async t => {
   assert_true(navigator.mediaDevices.getSupportedConstraints()["groupId"],
     "groupId should be supported");
+  const stream = await navigator.mediaDevices.getUserMedia({video:true});
+  stream.getVideoTracks()[0].stop();
   const devices = await navigator.mediaDevices.enumerateDevices();
   for (const device of devices) {
     await navigator.mediaDevices.getUserMedia(
@@ -63,6 +65,8 @@ promise_test(async t => {
 promise_test(async t => {
   assert_true(navigator.mediaDevices.getSupportedConstraints()["groupId"],
     "groupId should be supported");
+  const stream = await navigator.mediaDevices.getUserMedia({audio:true});
+  stream.getAudioTracks()[0].stop();
   const devices = await navigator.mediaDevices.enumerateDevices();
   for (const device of devices) {
     await navigator.mediaDevices.getUserMedia(
diff --git a/tests/wpt/web-platform-tests/mediacapture-streams/idlharness.https.window.js b/tests/wpt/web-platform-tests/mediacapture-streams/idlharness.https.window.js
index b10e8dbb046..ee5fb483c12 100644
--- a/tests/wpt/web-platform-tests/mediacapture-streams/idlharness.https.window.js
+++ b/tests/wpt/web-platform-tests/mediacapture-streams/idlharness.https.window.js
@@ -13,6 +13,8 @@ idl_test(
     const inputDevices = [];
     const outputDevices = [];
     try {
+      const stream = await navigator.mediaDevices.getUserMedia({audio:true, video:true});
+      stream.getTracks().forEach(track => track.stop());
       const list = await navigator.mediaDevices.enumerateDevices();
       for (const device of list) {
         if (device.kind in self) {
diff --git a/tests/wpt/web-platform-tests/tools/ci/pr_preview.py b/tests/wpt/web-platform-tests/tools/ci/pr_preview.py
index ba5997f68a6..2396e9b8aee 100755
--- a/tests/wpt/web-platform-tests/tools/ci/pr_preview.py
+++ b/tests/wpt/web-platform-tests/tools/ci/pr_preview.py
@@ -103,6 +103,15 @@ class Project(object):
         self._host = host
         self._github_project = github_project
 
+    @guard('core')
+    def get_pull_request(self, number):
+        url = '{}/repos/{}/pulls/{}'.format(
+            self._host, self._github_project, number
+        )
+
+        logger.info('Fetching Pull Request %s', number)
+        return gh_request('GET', url)
+
     @guard('search')
     def get_pull_requests(self, updated_since):
         window_start = time.strftime('%Y-%m-%dT%H:%M:%SZ', updated_since)
@@ -121,20 +130,18 @@ class Project(object):
         if data['incomplete_results']:
             raise Exception('Incomplete results')
 
-        return data['items']
+        return {pr['number']: pr for pr in data['items']}
 
-    @guard('core')
     def pull_request_is_from_fork(self, pull_request):
         pr_number = pull_request['number']
-        url = '{}/repos/{}/pulls/{}'.format(
-            self._host, self._github_project, pr_number
-        )
-
         logger.info('Checking if pull request %s is from a fork', pr_number)
 
-        data = gh_request('GET', url)
+        # We may already have this information; if so no need to make another
+        # API call.
+        if 'head' not in pull_request:
+            pull_request = self.get_pull_request(pr_number)
 
-        repo_name = data['head']['repo']['full_name']
+        repo_name = pull_request['head']['repo']['full_name']
         is_fork = repo_name != self._github_project
 
         logger.info(
@@ -222,13 +229,17 @@ class Remote(object):
         # for pushing changes.
         self._token = os.environ['DEPLOY_TOKEN']
 
-    def get_revision(self, refspec):
-        output = subprocess.check_output([
+    def _git(self, command):
+        return subprocess.check_output([
             'git',
             '-c',
             'credential.username={}'.format(self._token),
             '-c',
             'core.askPass=true',
+        ] + command)
+
+    def get_revision(self, refspec):
+        output = self._git([
             'ls-remote',
             'origin',
             'refs/{}'.format(refspec)
@@ -244,18 +255,40 @@ class Remote(object):
 
         logger.info('Deleting ref "%s"', refspec)
 
-        subprocess.check_call([
-            'git',
-            '-c',
-            'credential.username={}'.format(self._token),
-            '-c',
-            'core.askPass=true',
+        self._git([
             'push',
             'origin',
             '--delete',
             full_ref
         ])
 
+    def get_pull_requests_with_open_ref(self):
+        '''Returns pull requests that have an open ref.
+
+        This checks for all refs that match the pattern 'refs/prs-open/{pr}',
+        and then returns them as a list of pull request numbers. Note that this
+        method does not query github; this is only the open pull requests as
+        far as WPT knows.
+        '''
+
+        refspec = 'refs/prs-open/*'
+
+        logger.info('Fetching all ref names matching "%s"', refspec)
+
+        output = self._git([
+            'ls-remote',
+            'origin',
+            refspec,
+        ])
+
+        if not output:
+            return []
+
+        ref_names = [line.split()[1] for line in output.decode('utf-8').splitlines()]
+        logger.info('%s ref names found', len(ref_names))
+        return [int(ref_name.split('/')[2]) for ref_name in ref_names]
+
+
 def is_open(pull_request):
     return not pull_request['closed_at']
 
@@ -301,7 +334,19 @@ def synchronize(host, github_project, window):
         time.gmtime(time.time() - window)
     )
 
-    for pull_request in pull_requests:
+    # It is possible we may miss some pull requests if this script breaks or is
+    # not run for a while and the PR falls outside the checked window. To
+    # ensure that closed pull requests are deleted, extend the list of pull
+    # requests to look at with any that have an existing refs/prs-open/{pr} ref
+    # in the repo.
+    existing_pr_numbers = remote.get_pull_requests_with_open_ref()
+    for pr_number in existing_pr_numbers:
+        if pr_number in pull_requests:
+            continue
+        pull_request = project.get_pull_request(pr_number)
+        pull_requests[pull_request['number']] = pull_request
+
+    for pull_request in pull_requests.values():
         logger.info('Processing Pull Request #%(number)d', pull_request)
 
         refspec_trusted = 'prs-trusted-for-preview/{number}'.format(
diff --git a/tests/wpt/web-platform-tests/tools/ci/tests/test_pr_preview.py b/tests/wpt/web-platform-tests/tools/ci/tests/test_pr_preview.py
index 2d9966fc8cf..13aef508663 100644
--- a/tests/wpt/web-platform-tests/tools/ci/tests/test_pr_preview.py
+++ b/tests/wpt/web-platform-tests/tools/ci/tests/test_pr_preview.py
@@ -710,6 +710,44 @@ def test_synchronize_delete_collaborator():
     assert same_members(expected_traffic, actual_traffic)
     assert list(remote_refs) == ['refs/pull/23/head']
 
+
+def test_synchronize_delete_old_pr():
+    # No pull requests from the search, but one outstanding closed PR.
+    expected_traffic = [
+        (Requests.get_rate, Responses.no_limit),
+        (Requests.get_rate, Responses.no_limit),
+        (Requests.search, (200,
+            {
+                'items': [],
+                'incomplete_results': False
+            }
+        )),
+        (Requests.pr_details, (200,
+            {
+                'number': 23,
+                'labels': [],
+                'closed_at': '2019-10-28',
+                'head': {
+                    'repo': {
+                        'full_name': 'test-org/test-repo'
+                    }
+                }
+            }
+        )),
+    ]
+    refs = {
+        'refs/pull/23/head': 'HEAD',
+        'refs/prs-open/23': 'HEAD~',
+        'refs/prs-trusted-for-preview/23': 'HEAD~'
+    }
+
+    returncode, actual_traffic, remote_refs = synchronize(expected_traffic, refs)
+
+    assert returncode == 0
+    assert same_members(expected_traffic, actual_traffic)
+    assert list(remote_refs) == ['refs/pull/23/head']
+
+
 def test_detect_ignore_unknown_env():
     expected_github_traffic = []
     expected_preview_traffic = []
diff --git a/tests/wpt/web-platform-tests/tools/wpt/browser.py b/tests/wpt/web-platform-tests/tools/wpt/browser.py
index 6db3415a480..6abe1519484 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/browser.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/browser.py
@@ -558,7 +558,7 @@ class Chrome(Browser):
         with open(installer_path, "rb") as f:
             unzip(f, dest)
         os.remove(installer_path)
-        return self.find_nightly_binary(dest, channel)
+        return self.find_nightly_binary(dest)
 
     def install_mojojs(self, dest):
         url = self._latest_chromium_snapshot_url() + "mojojs.zip"
@@ -603,10 +603,12 @@ class Chrome(Browser):
             self._last_change = get(revision_url).text.strip()
         return "https://storage.googleapis.com/chromium-browser-snapshots/%s/%s/" % (architecture, self._last_change)
 
-    def find_nightly_binary(self, dest, channel):
-        binary = "Chromium" if uname[0] == "Darwin" else "chrome"
+    def find_nightly_binary(self, dest):
+        if uname[0] == "Darwin":
+            return find_executable("Chromium",
+                                   os.path.join(dest, self._chromium_package_name(), "Chromium.app", "Contents", "MacOS"))
         # find_executable will add .exe on Windows automatically.
-        return find_executable(binary, os.path.join(dest, self._chromium_package_name()))
+        return find_executable("chrome", os.path.join(dest, self._chromium_package_name()))
 
     def find_binary(self, venv_path=None, channel=None):
         if channel == "nightly":
diff --git a/tests/wpt/web-platform-tests/tools/wpt/tests/test_install.py b/tests/wpt/web-platform-tests/tools/wpt/tests/test_install.py
index 7d55d419c14..d1abbed142e 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/tests/test_install.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/tests/test_install.py
@@ -10,12 +10,13 @@ from tools.wpt import browser, utils, wpt
 @pytest.mark.slow
 @pytest.mark.remote_network
 def test_install_chromium():
+    dest = os.path.join(wpt.localpaths.repo_root, wpt.venv_dir(), "browsers", "nightly")
     if sys.platform == "win32":
-        chromium_path = os.path.join(wpt.localpaths.repo_root, wpt.venv_dir(), "browsers", "nightly", "chrome-win")
+        chromium_path = os.path.join(dest, "chrome-win")
     elif sys.platform == "darwin":
-        chromium_path = os.path.join(wpt.localpaths.repo_root, wpt.venv_dir(), "browsers", "nightly", "chrome-mac")
+        chromium_path = os.path.join(dest, "chrome-mac")
     else:
-        chromium_path = os.path.join(wpt.localpaths.repo_root, wpt.venv_dir(), "browsers", "nightly", "chrome-linux")
+        chromium_path = os.path.join(dest, "chrome-linux")
 
     if os.path.exists(chromium_path):
         utils.rmtree(chromium_path)
@@ -23,6 +24,11 @@ def test_install_chromium():
         wpt.main(argv=["install", "chrome", "browser", "--channel=nightly"])
     assert excinfo.value.code == 0
     assert os.path.exists(chromium_path)
+
+    chrome = browser.Chrome(logging.getLogger("Chrome"))
+    binary = chrome.find_nightly_binary(dest)
+    assert binary is not None and os.path.exists(binary)
+
     utils.rmtree(chromium_path)
 
 
diff --git a/tests/wpt/web-platform-tests/wasm/jsapi/namespace-object-class-string.any.js b/tests/wpt/web-platform-tests/wasm/jsapi/constructor/toStringTag.any.js
similarity index 97%
rename from tests/wpt/web-platform-tests/wasm/jsapi/namespace-object-class-string.any.js
rename to tests/wpt/web-platform-tests/wasm/jsapi/constructor/toStringTag.any.js
index 2f63aca2c55..9c0d346bc7e 100644
--- a/tests/wpt/web-platform-tests/wasm/jsapi/namespace-object-class-string.any.js
+++ b/tests/wpt/web-platform-tests/wasm/jsapi/constructor/toStringTag.any.js
@@ -1,3 +1,5 @@
+// META: global=window,dedicatedworker,jsshell
+
 "use strict";
 // https://heycam.github.io/webidl/#es-namespaces
 // https://webassembly.github.io/spec/js-api/#namespacedef-webassembly