diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-002.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-002.html.ini
new file mode 100644
index 00000000000..f64b45fea6b
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-002.html.ini
@@ -0,0 +1,4 @@
+[hit-test-floats-002.html]
+  [Hit test float]
+    expected: FAIL
+
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-003.html.ini
deleted file mode 100644
index f29da48a2a0..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-003.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-003.html]
-  [Miss float below something else]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
deleted file mode 100644
index 4bfb0c2053a..00000000000
--- a/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-004.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[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
new file mode 100644
index 00000000000..baa9f1a7541
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/css/CSS2/floats/hit-test-floats-005.html.ini
@@ -0,0 +1,4 @@
+[hit-test-floats-005.html]
+  [Miss clipped float]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/elementFromPoint-001.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/elementFromPoint-001.html.ini
deleted file mode 100644
index e38782d8c85..00000000000
--- a/tests/wpt/metadata-layout-2020/css/cssom-view/elementFromPoint-001.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[elementFromPoint-001.html]
-  [CSSOM View - 5 - extensions to the Document interface]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-invalid-cases.html.ini b/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-invalid-cases.html.ini
deleted file mode 100644
index e181af5397f..00000000000
--- a/tests/wpt/metadata-layout-2020/css/cssom-view/elementsFromPoint-invalid-cases.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[elementsFromPoint-invalid-cases.html]
-  [The root element is the last element returned for otherwise empty queries within the viewport]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini b/tests/wpt/metadata-layout-2020/fetch/content-type/response.window.js.ini
index a46b97e6be3..b3313a165c1 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 +312,18 @@
   [Response: combined response Content-Type: text/html;" \\" text/plain ";charset=GBK]
     expected: NOTRUN
 
-  [<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 */*]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: text/html;charset=gbk text/plain text/html]
-    expected: FAIL
-
-  [<iframe>: separate response Content-Type: text/html */*;charset=gbk]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
-    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/plain;charset=gbk text/html]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
+    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 2023a855086..87c807a49ff 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
@@ -11,6 +11,3 @@
   [X-Content-Type-Options%3A%20nosniff%0C]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20no%0D%0AX-Content-Type-Options%3A%20nosniff]
-    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_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/history/the-history-interface/traverse_the_history_5.html.ini b/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
deleted file mode 100644
index dc2e45516de..00000000000
--- a/tests/wpt/metadata-layout-2020/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_5.html]
-  [Multiple history traversals, last would be aborted]
-    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 ab43ed7acf4..295031c1812 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 +1,5 @@
 [iframe_sandbox_popups_escaping-3.html]
-  expected: CRASH
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
     expected: TIMEOUT
 
diff --git a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini
index 9d05ef1f801..60a5016a4e6 100644
--- a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini
+++ b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini
@@ -65,3 +65,6 @@
   [X Rendered audio for channel 5 does not equal [0,0.0626220703125,0.125030517578125,0.18695068359375,0.24810791015625,0.308319091796875,0.3673095703125,0.42486572265625,0.480743408203125,0.53472900390625,0.58660888671875,0.636199951171875,0.68328857421875,0.727691650390625,0.76922607421875,0.8077392578125...\] with an element-wise tolerance of {"absoluteThreshold":0.000030517578125,"relativeThreshold":0}.\n\tIndex\tActual\t\t\tExpected\t\tAbsError\t\tRelError\t\tTest threshold\n\t[1\]\t3.6732959747314453e-1\t6.2622070312500000e-2\t3.0470752716064453e-1\t4.8658168859649127e+0\t3.0517578125000000e-5\n\t[2\]\t6.8329977989196777e-1\t1.2503051757812500e-1\t5.5826926231384277e-1\t4.4650639949963384e+0\t3.0517578125000000e-5\n\t[3\]\t9.0373212099075317e-1\t1.8695068359375000e-1\t7.1678143739700317e-1\t3.8340669508039502e+0\t3.0517578125000000e-5\n\t[4\]\t9.9780619144439697e-1\t2.4810791015625000e-1\t7.4969828128814697e-1\t3.0216621502152523e+0\t3.0517578125000000e-5\n\t[5\]\t9.5236867666244507e-1\t3.0831909179687500e-1\t6.4404958486557007e-1\t2.0889059484187866e+0\t3.0517578125000000e-5\n\t...and 42300 more errors.\n\tMax AbsError of 1.9986611604690552e+0 at index of 23900.\n\t[23900\]\t-9.9994289875030518e-1\t9.9871826171875000e-1\t1.9986611604690552e+0\t2.0012262087101997e+0\t3.0517578125000000e-5\n\tMax RelError of Infinity at index of 7056.\n\t[7056\]\t5.8778524398803711e-1\t0.0000000000000000e+0\t5.8778524398803711e-1\tInfinity\t3.0517578125000000e-5\n]
     expected: FAIL
 
+  [X Rendered audio for channel 5 does not equal [0,0.0626220703125,0.125030517578125,0.18695068359375,0.24810791015625,0.308319091796875,0.3673095703125,0.42486572265625,0.480743408203125,0.53472900390625,0.58660888671875,0.636199951171875,0.68328857421875,0.727691650390625,0.76922607421875,0.8077392578125...\] with an element-wise tolerance of {"absoluteThreshold":0.000030517578125,"relativeThreshold":0}.\n\tIndex\tActual\t\t\tExpected\t\tAbsError\t\tRelError\t\tTest threshold\n\t[1\]\t3.6732959747314453e-1\t6.2622070312500000e-2\t3.0470752716064453e-1\t4.8658168859649127e+0\t3.0517578125000000e-5\n\t[2\]\t6.8329977989196777e-1\t1.2503051757812500e-1\t5.5826926231384277e-1\t4.4650639949963384e+0\t3.0517578125000000e-5\n\t[3\]\t9.0373212099075317e-1\t1.8695068359375000e-1\t7.1678143739700317e-1\t3.8340669508039502e+0\t3.0517578125000000e-5\n\t[4\]\t9.9780619144439697e-1\t2.4810791015625000e-1\t7.4969828128814697e-1\t3.0216621502152523e+0\t3.0517578125000000e-5\n\t[5\]\t9.5236867666244507e-1\t3.0831909179687500e-1\t6.4404958486557007e-1\t2.0889059484187866e+0\t3.0517578125000000e-5\n\t...and 44053 more errors.\n\tMax AbsError of 1.9999977350234985e+0 at index of 28001.\n\t[28001\]\t9.9999773502349854e-1\t-1.0000000000000000e+0\t1.9999977350234985e+0\t1.9999977350234985e+0\t3.0517578125000000e-5\n\tMax RelError of Infinity at index of 12348.\n\t[12348\]\t9.5105654001235962e-1\t0.0000000000000000e+0\t9.5105654001235962e-1\tInfinity\t3.0517578125000000e-5\n]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini
index 07b7337bb30..7d458325041 100644
--- a/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini
+++ b/tests/wpt/metadata-layout-2020/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini
@@ -107,3 +107,6 @@
   [X SNR (-397.687000526132 dB) is not greater than or equal to 85.58. Got -397.687000526132.]
     expected: FAIL
 
+  [X Stitched sine-wave buffers at sample rate 44100 does not equal [0,0.06264832615852356,0.12505052983760834,0.18696144223213196,0.24813786149024963,0.308339387178421,0.36732959747314453,0.4248766601085663,0.480754554271698,0.5347436666488647,0.5866320133209229,0.6362156271934509,0.6832997798919678,0.7276994585990906,0.7692402601242065,0.8077589869499207...\] with an element-wise tolerance of {"absoluteThreshold":0.000090957,"relativeThreshold":0}.\n\tIndex\tActual\t\t\tExpected\t\tAbsError\t\tRelError\t\tTest threshold\n\t[31080\]\t-3.0409904191139748e-29\t5.6332010030746460e-1\t5.6332010030746460e-1\t1.0000000000000000e+0\t9.0957000000000003e-5\n\t[31081\]\t4.5842077961922066e-41\t6.1397600173950195e-1\t6.1397600173950195e-1\t1.0000000000000000e+0\t9.0957000000000003e-5\n\tMax AbsError of 6.1397600173950195e-1 at index of 31081.\n\tMax RelError of 1.0000000000000000e+0 at index of 31080.\n]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata-layout-2020/workers/WorkerGlobalScope-close.html.ini b/tests/wpt/metadata-layout-2020/workers/WorkerGlobalScope-close.html.ini
new file mode 100644
index 00000000000..fe8654e447c
--- /dev/null
+++ b/tests/wpt/metadata-layout-2020/workers/WorkerGlobalScope-close.html.ini
@@ -0,0 +1,4 @@
+[WorkerGlobalScope-close.html]
+  [Test sending a message after closing.]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 54899242d11..7d8cd33e49c 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -457,6 +457,15 @@
      ]
     ]
    },
+   "selection": {
+    "selection-select-all-move-input-crash.html": [
+     "6f692dc5e7d69a30a407f107268c9e012efcd9e3",
+     [
+      null,
+      {}
+     ]
+    ]
+   },
    "svg": {
     "animations": {
      "end-of-time-crash.html": [
@@ -161331,6 +161340,86 @@
      }
     },
     "css-sizing": {
+     "aspect-ratio": {
+      "flex-aspect-ratio-001.tentative.html": [
+       "3b477e299ad763a1c0108e16f05981c76c25bb77",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "flex-aspect-ratio-002.tentative.html": [
+       "d7714f07e774baadc5231b43c5cf71d08dcea487",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "flex-aspect-ratio-003.tentative.html": [
+       "85775fa8c067c942ce97aa668ac4179949c06dd6",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "flex-aspect-ratio-004.tentative.html": [
+       "05b569ac607185b186221bbdb8edfb40fa153662",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "flex-aspect-ratio-005.tentative.html": [
+       "2b13df2184fcbdd869bd5e954d87c70c449a2365",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ],
+      "flex-aspect-ratio-006.tentative.html": [
+       "f4667cfc1fd689c7e11bfb38dc64ff3212064a29",
+       [
+        null,
+        [
+         [
+          "/css/reference/ref-filled-green-100px-square.xht",
+          "=="
+         ]
+        ],
+        {}
+       ]
+      ]
+     },
      "auto-scrollbar-inside-stf-abspos.html": [
       "9479b2eb3f51aed98741beadff4a8407b3ae9f33",
       [
@@ -203776,6 +203865,19 @@
        {}
       ]
      ],
+     "filter-effect-remove-unattached.html": [
+      "cfb11af605e777e968818f424110a6cdea5b4a48",
+      [
+       null,
+       [
+        [
+         "/css/filter-effects/reference/filter-effect-remove-unattached-ref.html",
+         "=="
+        ]
+       ],
+       {}
+      ]
+     ],
      "filter-external-001-test.html": [
       "588263c57c4d770642e1934608341a1e3bea76cb",
       [
@@ -226918,6 +227020,21 @@
     },
     "editing": {
      "editing-0": {
+      "contenteditable": {
+       "contenteditable-with-empty-block.html": [
+        "7bcc6110723643f3a26f39420586e5ead549d7eb",
+        [
+         null,
+         [
+          [
+           "/html/editing/editing-0/contenteditable/contenteditable-with-empty-block-ref.html",
+           "=="
+          ]
+         ],
+         {}
+        ]
+       ]
+      },
       "spelling-and-grammar-checking": {
        "spelling-markers-001.html": [
         "7dd891374bcdd40c7b88f9a2b693945d62077054",
@@ -308069,6 +308186,10 @@
        "cf2c997f6c0d60cac9896c0b0014189cea7790bc",
        []
       ],
+      "filter-effect-remove-unattached-ref.html": [
+       "5f9f7a76ec71bfa5abe4a0a82bc126af8fa0ad5a",
+       []
+      ],
       "filter-region-negative-positioned-child-001-ref.html": [
        "c9da47b1b434303f0111e8d1f03d5518e8f573fc",
        []
@@ -308134,6 +308255,12 @@
        []
       ]
      },
+     "resources": {
+      "reference.png": [
+       "68641b76771abf086dc213b353ac2088fffb931a",
+       []
+      ]
+     },
      "support": {
       "1x1-green.png": [
        "b98ca0ba0a03c580ac339e4a3653539cfa8edc71",
@@ -323333,6 +323460,12 @@
       }
      },
      "editing-0": {
+      "contenteditable": {
+       "contenteditable-with-empty-block-ref.html": [
+        "fe68571013cc4cb98227fec47bdb0f8cd2e74410",
+        []
+       ]
+      },
       "making-entire-documents-editable-the-designmode-idl-attribute": {
        "original-id.json": [
         "8b7c4b838c26b55b2bf21bf23d6d08634399f63a",
@@ -344297,7 +344430,7 @@
         []
        ],
        "firefox.py": [
-        "3fbfbfaac81371c774cbb1ac8e96de27fa3c854b",
+        "bfc3ab9a2be5e399738cece75ec8846e069207eb",
         []
        ],
        "firefox_android.py": [
@@ -482949,7 +483082,7 @@
      ]
     ],
     "slots-imperative-slot-api.tentative.html": [
-     "6d3997b085c99b5163f1f1a747b792a5dbca9dea",
+     "6343886da036d8ba09daf8d7d0fe2a8cd7949d48",
      [
       null,
       {}
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-002.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-002.html.ini
new file mode 100644
index 00000000000..f64b45fea6b
--- /dev/null
+++ b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-002.html.ini
@@ -0,0 +1,4 @@
+[hit-test-floats-002.html]
+  [Hit test float]
+    expected: FAIL
+
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-003.html.ini
deleted file mode 100644
index f29da48a2a0..00000000000
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-003.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[hit-test-floats-003.html]
-  [Miss float below something else]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
deleted file mode 100644
index 4bfb0c2053a..00000000000
--- a/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-004.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[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
new file mode 100644
index 00000000000..baa9f1a7541
--- /dev/null
+++ b/tests/wpt/metadata/css/CSS2/floats/hit-test-floats-005.html.ini
@@ -0,0 +1,4 @@
+[hit-test-floats-005.html]
+  [Miss clipped float]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/cssom-view/elementFromPoint-001.html.ini b/tests/wpt/metadata/css/cssom-view/elementFromPoint-001.html.ini
deleted file mode 100644
index e38782d8c85..00000000000
--- a/tests/wpt/metadata/css/cssom-view/elementFromPoint-001.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[elementFromPoint-001.html]
-  [CSSOM View - 5 - extensions to the Document interface]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/css/cssom-view/elementsFromPoint-invalid-cases.html.ini b/tests/wpt/metadata/css/cssom-view/elementsFromPoint-invalid-cases.html.ini
deleted file mode 100644
index e181af5397f..00000000000
--- a/tests/wpt/metadata/css/cssom-view/elementsFromPoint-invalid-cases.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[elementsFromPoint-invalid-cases.html]
-  [The root element is the last element returned for otherwise empty queries within the viewport]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/fetch/content-type/response.window.js.ini b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
index 42843b8ce63..78de5ebec3f 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 +312,18 @@
   [fetch(): separate response Content-Type: text/plain ]
     expected: NOTRUN
 
-  [<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 */*]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: text/html;charset=gbk text/plain text/html]
-    expected: FAIL
-
-  [<iframe>: separate response Content-Type: text/html */*;charset=gbk]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
-    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/plain;charset=gbk text/html]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
+    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 70efd28ddfc..30e1b851fd4 100644
--- a/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
+++ b/tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini
@@ -11,6 +11,3 @@
   [X-Content-Type-Options%3A%20nosniff%2C%2C%40%23%24%23%25%25%26%5E%26%5E*()()11!]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20no%0D%0AX-Content-Type-Options%3A%20nosniff]
-    expected: FAIL
-
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_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/history/the-history-interface/traverse_the_history_5.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
deleted file mode 100644
index dc2e45516de..00000000000
--- a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_5.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[traverse_the_history_5.html]
-  [Multiple history traversals, last would be aborted]
-    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 b3bd9f4c289..5f60c78e73c 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 +1,6 @@
 [iframe_sandbox_popups_escaping-3.html]
   type: testharness
-  expected: CRASH
+  expected: TIMEOUT
   [Check that popups from a sandboxed iframe escape the sandbox if\n       allow-popups-to-escape-sandbox is used]
     expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini
index 1f47978311d..93b59ad6eb8 100644
--- a/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/audiobuffersource-multi-channels.html.ini
@@ -134,3 +134,6 @@
   [X Rendered audio for channel 5 does not equal [0,0.0626220703125,0.125030517578125,0.18695068359375,0.24810791015625,0.308319091796875,0.3673095703125,0.42486572265625,0.480743408203125,0.53472900390625,0.58660888671875,0.636199951171875,0.68328857421875,0.727691650390625,0.76922607421875,0.8077392578125...\] with an element-wise tolerance of {"absoluteThreshold":0.000030517578125,"relativeThreshold":0}.\n\tIndex\tActual\t\t\tExpected\t\tAbsError\t\tRelError\t\tTest threshold\n\t[1\]\t3.6732959747314453e-1\t6.2622070312500000e-2\t3.0470752716064453e-1\t4.8658168859649127e+0\t3.0517578125000000e-5\n\t[2\]\t6.8329977989196777e-1\t1.2503051757812500e-1\t5.5826926231384277e-1\t4.4650639949963384e+0\t3.0517578125000000e-5\n\t[3\]\t9.0373212099075317e-1\t1.8695068359375000e-1\t7.1678143739700317e-1\t3.8340669508039502e+0\t3.0517578125000000e-5\n\t[4\]\t9.9780619144439697e-1\t2.4810791015625000e-1\t7.4969828128814697e-1\t3.0216621502152523e+0\t3.0517578125000000e-5\n\t[5\]\t9.5236867666244507e-1\t3.0831909179687500e-1\t6.4404958486557007e-1\t2.0889059484187866e+0\t3.0517578125000000e-5\n\t...and 42300 more errors.\n\tMax AbsError of 1.9986611604690552e+0 at index of 23900.\n\t[23900\]\t-9.9994289875030518e-1\t9.9871826171875000e-1\t1.9986611604690552e+0\t2.0012262087101997e+0\t3.0517578125000000e-5\n\tMax RelError of Infinity at index of 7056.\n\t[7056\]\t5.8778524398803711e-1\t0.0000000000000000e+0\t5.8778524398803711e-1\tInfinity\t3.0517578125000000e-5\n]
     expected: FAIL
 
+  [X Rendered audio for channel 5 does not equal [0,0.0626220703125,0.125030517578125,0.18695068359375,0.24810791015625,0.308319091796875,0.3673095703125,0.42486572265625,0.480743408203125,0.53472900390625,0.58660888671875,0.636199951171875,0.68328857421875,0.727691650390625,0.76922607421875,0.8077392578125...\] with an element-wise tolerance of {"absoluteThreshold":0.000030517578125,"relativeThreshold":0}.\n\tIndex\tActual\t\t\tExpected\t\tAbsError\t\tRelError\t\tTest threshold\n\t[1\]\t3.6732959747314453e-1\t6.2622070312500000e-2\t3.0470752716064453e-1\t4.8658168859649127e+0\t3.0517578125000000e-5\n\t[2\]\t6.8329977989196777e-1\t1.2503051757812500e-1\t5.5826926231384277e-1\t4.4650639949963384e+0\t3.0517578125000000e-5\n\t[3\]\t9.0373212099075317e-1\t1.8695068359375000e-1\t7.1678143739700317e-1\t3.8340669508039502e+0\t3.0517578125000000e-5\n\t[4\]\t9.9780619144439697e-1\t2.4810791015625000e-1\t7.4969828128814697e-1\t3.0216621502152523e+0\t3.0517578125000000e-5\n\t[5\]\t9.5236867666244507e-1\t3.0831909179687500e-1\t6.4404958486557007e-1\t2.0889059484187866e+0\t3.0517578125000000e-5\n\t...and 44053 more errors.\n\tMax AbsError of 1.9999977350234985e+0 at index of 28001.\n\t[28001\]\t9.9999773502349854e-1\t-1.0000000000000000e+0\t1.9999977350234985e+0\t1.9999977350234985e+0\t3.0517578125000000e-5\n\tMax RelError of Infinity at index of 12348.\n\t[12348\]\t9.5105654001235962e-1\t0.0000000000000000e+0\t9.5105654001235962e-1\tInfinity\t3.0517578125000000e-5\n]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini
index bf6a53ab8b2..c1d7882c6a4 100644
--- a/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-audiobuffersourcenode-interface/sub-sample-buffer-stitching.html.ini
@@ -338,3 +338,6 @@
   [X SNR (-397.687000526132 dB) is not greater than or equal to 85.58. Got -397.687000526132.]
     expected: FAIL
 
+  [X Stitched sine-wave buffers at sample rate 44100 does not equal [0,0.06264832615852356,0.12505052983760834,0.18696144223213196,0.24813786149024963,0.308339387178421,0.36732959747314453,0.4248766601085663,0.480754554271698,0.5347436666488647,0.5866320133209229,0.6362156271934509,0.6832997798919678,0.7276994585990906,0.7692402601242065,0.8077589869499207...\] with an element-wise tolerance of {"absoluteThreshold":0.000090957,"relativeThreshold":0}.\n\tIndex\tActual\t\t\tExpected\t\tAbsError\t\tRelError\t\tTest threshold\n\t[31080\]\t-3.0409904191139748e-29\t5.6332010030746460e-1\t5.6332010030746460e-1\t1.0000000000000000e+0\t9.0957000000000003e-5\n\t[31081\]\t4.5842077961922066e-41\t6.1397600173950195e-1\t6.1397600173950195e-1\t1.0000000000000000e+0\t9.0957000000000003e-5\n\tMax AbsError of 6.1397600173950195e-1 at index of 31081.\n\tMax RelError of 1.0000000000000000e+0 at index of 31080.\n]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/workers/WorkerGlobalScope-close.html.ini b/tests/wpt/metadata/workers/WorkerGlobalScope-close.html.ini
new file mode 100644
index 00000000000..fe8654e447c
--- /dev/null
+++ b/tests/wpt/metadata/workers/WorkerGlobalScope-close.html.ini
@@ -0,0 +1,4 @@
+[WorkerGlobalScope-close.html]
+  [Test sending a message after closing.]
+    expected: FAIL
+
diff --git a/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-001.tentative.html b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-001.tentative.html
new file mode 100644
index 00000000000..3b477e299ad
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-001.tentative.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<title>CSS aspect-ratio: Row flexbox main size</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#line-sizing" title="9.2.3.B">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht" />
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div style="display: flex;">
+  <div style="background: green; height: 100px; aspect-ratio: 1/1; min-width: 0;"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-002.tentative.html b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-002.tentative.html
new file mode 100644
index 00000000000..d7714f07e77
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-002.tentative.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<title>CSS aspect-ratio: Row flexbox min-width</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#min-size-auto">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht" />
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div style="display: flex;">
+  <!-- transferred size: 100px. content size suggestion: 200px.
+       min-width: min(100, 200). -->
+  <div style="background: green; height: 100px; aspect-ratio: 1/1; flex-basis: 0;">
+    <div style="width: 200px;"></div>
+  </div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-003.tentative.html b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-003.tentative.html
new file mode 100644
index 00000000000..85775fa8c06
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-003.tentative.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<title>CSS aspect-ratio: Column flexbox main size</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#line-sizing" title="9.2.3.B">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht" />
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div style="display: flex; flex-direction: column;">
+  <div style="background: green; width: 100px; aspect-ratio: 1/1; min-height: 0;"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-004.tentative.html b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-004.tentative.html
new file mode 100644
index 00000000000..05b569ac607
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-004.tentative.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<title>CSS aspect-ratio: Column flexbox min-height</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#min-size-auto">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht" />
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div style="display: flex; flex-direction: column;">
+  <!-- transferred size: 100px. content size suggestion: 200px.
+       min-height: min(100, 200). -->
+  <div style="background: green; width: 100px; aspect-ratio: 1/1; flex-basis: 0;">
+    <div style="height: 200px;"></div>
+  </div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-005.tentative.html b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-005.tentative.html
new file mode 100644
index 00000000000..2b13df2184f
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-005.tentative.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<title>CSS aspect-ratio: Non-square aspect ratio in Flexbox</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#line-sizing" title="9.2.3.B">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht" />
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div style="display: flex;">
+  <div style="background: green; height: 100px; aspect-ratio: 1/2; min-width: 0;"></div>
+  <div style="background: green; width: 50px; height: 100px;"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-006.tentative.html b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-006.tentative.html
new file mode 100644
index 00000000000..f4667cfc1fd
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-sizing/aspect-ratio/flex-aspect-ratio-006.tentative.html
@@ -0,0 +1,13 @@
+<!DOCTYPE html>
+<title>CSS aspect-ratio: Vertical writing mode in Flexbox</title>
+<link rel="author" title="Google LLC" href="https://www.google.com/">
+<link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio">
+<link rel="help" href="https://drafts.csswg.org/css-flexbox/#line-sizing" title="9.2.3.B">
+<link rel="match" href="../../reference/ref-filled-green-100px-square.xht" />
+
+<p>Test passes if there is a filled green square and <strong>no red</strong>.</p>
+
+<div style="display: flex;">
+  <div style="background: green; height: 100px; aspect-ratio: 1/2; min-width: 0; writing-mode: vertical-lr;"></div>
+  <div style="background: green; width: 50px; height: 100px;"></div>
+</div>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/filter-effect-remove-unattached.html b/tests/wpt/web-platform-tests/css/filter-effects/filter-effect-remove-unattached.html
new file mode 100644
index 00000000000..cfb11af605e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/filter-effects/filter-effect-remove-unattached.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+<title>CSS Filters: Remove a filter effect from an unattached element</title>
+<link rel="author" title="Ali Juma" href="mailto:ajuma@chromium.org">
+<link rel="help" href="https://drafts.fxtf.org/filter-effects/#FilterProperty">
+<link rel="help" href="https://drafts.fxtf.org/filter-effects-1/#feGaussianBlurElement">
+<link rel="issue" href="https://bugs.chromium.org/p/chromium/issues/detail?id=502026">
+<link rel="match" href="reference/filter-effect-remove-unattached-ref.html">
+<meta name="assert" content="This test ensures that we can remove a filter effect from an unattached element.">
+<script src="/common/reftest-wait.js"></script>
+<svg xmlns="http://www.w3.org/2000/svg" width="0" height="0" version="1.1">
+  <defs id="svgDefs" style="display:none">
+   <filter id="blurY" color-interpolation-filters="sRGB">
+    <feGaussianBlur id="blurEffect" stdDeviation="0 5">
+    </feGaussianBlur>
+   </filter>
+  </defs>
+</svg>
+
+<script>
+  onload = function() {
+    // Render one frame with the blur effect, then remove it.
+    window.requestAnimationFrame(function() {
+      window.requestAnimationFrame(function() {
+        var filterElement = document.getElementById("blurY");
+        var filterEffectElement = document.getElementById("blurEffect");
+        filterElement.removeChild(filterEffectElement);
+
+        // Ensure we draw a frame.
+        document.getElementById("other").style.backgroundColor = "blue";
+        takeScreenshot();
+      });
+    });
+  }
+</script>
+
+<img src="resources/reference.png" style="filter: url(#blurY);">
+
+<div id="other" style="width: 10px; height: 10px"></div>
+</html>
\ No newline at end of file
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/reference/filter-effect-remove-unattached-ref.html b/tests/wpt/web-platform-tests/css/filter-effects/reference/filter-effect-remove-unattached-ref.html
new file mode 100644
index 00000000000..5f9f7a76ec7
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/filter-effects/reference/filter-effect-remove-unattached-ref.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+  <svg xmlns="http://www.w3.org/2000/svg" width="0" height="0" version="1.1">
+  <defs id="svgDefs" style="display:none">
+   <filter id="blurY" color-interpolation-filters="sRGB">
+   </filter>
+  </defs>
+ </svg>
+
+<img src="../resources/reference.png" style="filter: url(#blurY);">
+
+<div id="other" style="width: 10px; height: 10px; background-color: blue;"></div>
diff --git a/tests/wpt/web-platform-tests/css/filter-effects/resources/reference.png b/tests/wpt/web-platform-tests/css/filter-effects/resources/reference.png
new file mode 100644
index 00000000000..68641b76771
Binary files /dev/null and b/tests/wpt/web-platform-tests/css/filter-effects/resources/reference.png differ
diff --git a/tests/wpt/web-platform-tests/html/editing/editing-0/contenteditable/contenteditable-with-empty-block-ref.html b/tests/wpt/web-platform-tests/html/editing/editing-0/contenteditable/contenteditable-with-empty-block-ref.html
new file mode 100644
index 00000000000..fe68571013c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/editing/editing-0/contenteditable/contenteditable-with-empty-block-ref.html
@@ -0,0 +1,7 @@
+<!doctype html>
+<title>Test reference</title>
+<div>
+  Foo
+  <div></div>
+  Bar
+</div>
diff --git a/tests/wpt/web-platform-tests/html/editing/editing-0/contenteditable/contenteditable-with-empty-block.html b/tests/wpt/web-platform-tests/html/editing/editing-0/contenteditable/contenteditable-with-empty-block.html
new file mode 100644
index 00000000000..7bcc6110723
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/editing/editing-0/contenteditable/contenteditable-with-empty-block.html
@@ -0,0 +1,11 @@
+<!doctype html>
+<title>contenteditable doesn't cause inner empty blocks to grow.</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1628770">
+<link rel="match" href="contenteditable-with-empty-block-ref.html">
+<div contenteditable>
+  Foo
+  <div></div>
+  Bar
+</div>
diff --git a/tests/wpt/web-platform-tests/selection/selection-select-all-move-input-crash.html b/tests/wpt/web-platform-tests/selection/selection-select-all-move-input-crash.html
new file mode 100644
index 00000000000..6f692dc5e7d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/selection/selection-select-all-move-input-crash.html
@@ -0,0 +1,10 @@
+<script>
+  function start() {
+    document.execCommand('selectAll', false)
+    document.documentElement.appendChild(document.getElementById('input'))
+  }
+</script>
+<body onload="start()">
+<input id="input" autofocus>
+<canvas contenteditable="true" hidden></canvas>
+</body>
diff --git a/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-slot-api.tentative.html b/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-slot-api.tentative.html
index 6d3997b085c..6343886da03 100644
--- a/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-slot-api.tentative.html
+++ b/tests/wpt/web-platform-tests/shadow-dom/slots-imperative-slot-api.tentative.html
@@ -277,4 +277,29 @@ test(() => {
   assert_equals(tTree.c2.assignedSlot, null);
   assert_equals(tTree.c3.assignedSlot, null);
 }, 'Removing a slot from DOM resets its slotable\'s slot assignment.');
+
+test(() => {
+  let tTree = createTestTree(test_assign);
+
+  tTree.s1.assign([tTree.c1]);
+  tTree.s2.assign([tTree.c2]);
+  tTree.s3.assign([tTree.c3]);
+  tTree.shadow_root.insertBefore(tTree.s2, tTree.s1);
+  tTree.shadow_root.insertBefore(tTree.s3, tTree.s1);
+
+  assert_array_equals(tTree.s1.assignedNodes(), [tTree.c1]);
+  assert_array_equals(tTree.s2.assignedNodes(), []);
+  assert_array_equals(tTree.s3.assignedNodes(), []);
+  assert_equals(tTree.c1.assignedSlot, tTree.s1);
+  assert_equals(tTree.c2.assignedSlot, null);
+  assert_equals(tTree.c3.assignedSlot, null);
+
+  tTree.s2.remove();
+
+  assert_array_equals(tTree.s1.assignedNodes(), [tTree.c1]);
+  assert_array_equals(tTree.s3.assignedNodes(), []);
+  assert_equals(tTree.c1.assignedSlot, tTree.s1);
+  assert_equals(tTree.c2.assignedSlot, null);
+  assert_equals(tTree.c3.assignedSlot, null);
+}, 'A slot should be cleared of assigned nodes even if it\'s re-inserted into the same shadow root.');
 </script>
diff --git a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py
index 3fbfbfaac81..bfc3ab9a2be 100644
--- a/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py
+++ b/tests/wpt/web-platform-tests/tools/wptrunner/wptrunner/browsers/firefox.py
@@ -319,7 +319,7 @@ class SingleInstanceManager(FirefoxInstanceManager):
         return self.current
 
     def teardown(self, force=False):
-        for instance, skip_marionette in [self.previous, self.current]:
+        for instance in [self.previous, self.current]:
             if instance:
                 instance.stop(force)
                 instance.cleanup()
@@ -345,11 +345,14 @@ class PreloadInstanceManager(FirefoxInstanceManager):
         return self.current
 
     def teardown(self, force=False):
-        for instance, skip_marionette in [(self.previous, False), (self.current, False), (self.pending, True)]:
+        for instance, skip_marionette in [(self.previous, False),
+                                          (self.current, False),
+                                          (self.pending, True)]:
             if instance:
                 instance.stop(force, skip_marionette=skip_marionette)
                 instance.cleanup()
 
+
 class BrowserInstance(object):
     shutdown_timeout = 70