diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index beb1de8736a..5d2f68f56a7 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -201221,6 +201221,54 @@
      {}
     ]
    ],
+   "mathml/presentation-markup/operators/mo-form-dynamic.html": [
+    [
+     "mathml/presentation-markup/operators/mo-form-dynamic.html",
+     [
+      [
+       "/mathml/presentation-markup/operators/mo-form-dynamic-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
+   "mathml/presentation-markup/operators/mo-form-fallback.html": [
+    [
+     "mathml/presentation-markup/operators/mo-form-fallback.html",
+     [
+      [
+       "/mathml/presentation-markup/operators/mo-form-fallback-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
+   "mathml/presentation-markup/operators/mo-form-minus-plus.html": [
+    [
+     "mathml/presentation-markup/operators/mo-form-minus-plus.html",
+     [
+      [
+       "/mathml/presentation-markup/operators/mo-form-minus-plus-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
+   "mathml/presentation-markup/operators/mo-form.html": [
+    [
+     "mathml/presentation-markup/operators/mo-form.html",
+     [
+      [
+       "/mathml/presentation-markup/operators/mo-form-ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
    "mathml/presentation-markup/operators/mo-paint-lspace-rspace.html": [
     [
      "mathml/presentation-markup/operators/mo-paint-lspace-rspace.html",
@@ -270469,6 +270517,18 @@
    "mathml/presentation-markup/fractions/frac-visibility-001-ref.html": [
     []
    ],
+   "mathml/presentation-markup/operators/mo-form-dynamic-ref.html": [
+    []
+   ],
+   "mathml/presentation-markup/operators/mo-form-fallback-ref.html": [
+    []
+   ],
+   "mathml/presentation-markup/operators/mo-form-minus-plus-ref.html": [
+    []
+   ],
+   "mathml/presentation-markup/operators/mo-form-ref.html": [
+    []
+   ],
    "mathml/presentation-markup/operators/mo-paint-lspace-rspace-ref.html": [
     []
    ],
@@ -274486,10 +274546,10 @@
    "resources/test/tests/unit/IdlInterfaceMember/is_to_json_regular_operation.html": [
     []
    ],
-   "resources/test/tests/unit/META.yml": [
+   "resources/test/tests/unit/basic.html": [
     []
    ],
-   "resources/test/tests/unit/basic.html": [
+   "resources/test/tests/unit/exceptional-cases-timeouts.html": [
     []
    ],
    "resources/test/tests/unit/exceptional-cases.html": [
@@ -277828,6 +277888,9 @@
    "tools/ci/azure/install_chrome.yml": [
     []
    ],
+   "tools/ci/azure/install_edge.yml": [
+    []
+   ],
    "tools/ci/azure/install_firefox.yml": [
     []
    ],
@@ -315024,6 +315087,30 @@
      {}
     ]
    ],
+   "css/css-text-decor/text-decoration-width-computed.html": [
+    [
+     "css/css-text-decor/text-decoration-width-computed.html",
+     {}
+    ]
+   ],
+   "css/css-text-decor/text-decoration-width-initial.html": [
+    [
+     "css/css-text-decor/text-decoration-width-initial.html",
+     {}
+    ]
+   ],
+   "css/css-text-decor/text-decoration-width-invalid.html": [
+    [
+     "css/css-text-decor/text-decoration-width-invalid.html",
+     {}
+    ]
+   ],
+   "css/css-text-decor/text-decoration-width-valid.html": [
+    [
+     "css/css-text-decor/text-decoration-width-valid.html",
+     {}
+    ]
+   ],
    "css/css-text-decor/text-emphasis-unrepresentable-characters.html": [
     [
      "css/css-text-decor/text-emphasis-unrepresentable-characters.html",
@@ -391950,6 +392037,12 @@
      {}
     ]
    ],
+   "svg/extensibility/foreignObject/foreign-object-under-defs-crash.html": [
+    [
+     "svg/extensibility/foreignObject/foreign-object-under-defs-crash.html",
+     {}
+    ]
+   ],
    "svg/extensibility/foreignObject/properties.svg": [
     [
      "svg/extensibility/foreignObject/properties.svg",
@@ -431392,7 +431485,7 @@
  },
  "paths": {
   ".azure-pipelines.yml": [
-   "99873aece5caff1c997c55e5c56db518730a0c1b",
+   "72a509e6b19d2d1e3b1b47e134eac8c94eb3bb5f",
    "support"
   ],
   ".codecov.yml": [
@@ -437948,7 +438041,7 @@
    "support"
   ],
   "WebIDL/META.yml": [
-   "a8dc9c4410e949fa78bdbe2268edf3f125934487",
+   "6aaee0e2694d6d46b86e2ad868d3fae949c6438a",
    "support"
   ],
   "WebIDL/current-realm.html": [
@@ -561699,6 +561792,22 @@
    "904460a7bfeef5a35261641422a5fde2dd07dce4",
    "visual"
   ],
+  "css/css-text-decor/text-decoration-width-computed.html": [
+   "0e00240141ea45ac95e8778474df3472afaf766c",
+   "testharness"
+  ],
+  "css/css-text-decor/text-decoration-width-initial.html": [
+   "ee47af0f115d29705b2cb485af63ecec67b5645e",
+   "testharness"
+  ],
+  "css/css-text-decor/text-decoration-width-invalid.html": [
+   "e89fe47ff2d567db6eae913a49d3abe2d62eaa7c",
+   "testharness"
+  ],
+  "css/css-text-decor/text-decoration-width-valid.html": [
+   "583ebb0d3cf52d5af73da39f979e2c1d90ffa8ea",
+   "testharness"
+  ],
   "css/css-text-decor/text-emphasis-color-001.xht": [
    "b60f03591ed067b8a8411cdad2ea8bcd222a37fc",
    "reftest"
@@ -574560,7 +574669,7 @@
    "testharness"
   ],
   "css/css-typed-om/the-stylepropertymap/properties/animation-timing-function.html": [
-   "b66d64c9b9a100bdd91c1c400c5e514ca9fbe4fc",
+   "eb9af36a85ae454d29ab18d2fa9b5d8dabb699dd",
    "testharness"
   ],
   "css/css-typed-om/the-stylepropertymap/properties/animation.html": [
@@ -575388,7 +575497,7 @@
    "testharness"
   ],
   "css/css-typed-om/the-stylepropertymap/properties/transition-timing-function.html": [
-   "5d3260f7a51bda2a1b50ccc229b876bc72ef45d1",
+   "a4dbfc19330e6d447b40589f6ad737f5bab6a9c8",
    "testharness"
   ],
   "css/css-typed-om/the-stylepropertymap/properties/transition.html": [
@@ -575472,7 +575581,7 @@
    "reftest"
   ],
   "css/css-ui/appearance-cssom-001.html": [
-   "2d439ba615f30f348128a3d94c6ea6563993e09b",
+   "f7dd4d1d761ed57831ae7842280f47164c6c080e",
    "testharness"
   ],
   "css/css-ui/appearance-listbox-001.html": [
@@ -607304,7 +607413,7 @@
    "testharness"
   ],
   "fetch/api/request/destination/fetch-destination-worker.https.html": [
-   "8421d4ac9ef66e743af2c834ecf466b07a14d16f",
+   "5935c1ff31ec4bf84b65fc2a92ff7276f4e79fed",
    "testharness"
   ],
   "fetch/api/request/destination/fetch-destination.https.html": [
@@ -630592,7 +630701,7 @@
    "support"
   ],
   "interfaces/webxr.idl": [
-   "63327a3f55d79f1acdc2cbd53a98b0a089aade2d",
+   "9b48a0f904026752510d90e05b85652062d87088",
    "support"
   ],
   "interfaces/worklets.idl": [
@@ -631108,7 +631217,7 @@
    "testharness"
   ],
   "lint.whitelist": [
-   "04738ee972705391dddef4031a8f7cb429a9e068",
+   "c788ddd5fd61bc1fae193fccc3b4a71247cafa16",
    "support"
   ],
   "loading/preloader-css-import-no-quote.tentative.html": [
@@ -631308,15 +631417,15 @@
    "support"
   ],
   "mathml/presentation-markup/fractions/frac-created-dynamically-2.html": [
-   "4c8b7e303bd9b81a7fc3b25c3206f6f0f88f6e81",
+   "a9707071a0624c7701cef46ff7e3746fb3feeb00",
    "reftest"
   ],
   "mathml/presentation-markup/fractions/frac-created-dynamically-3-ref.html": [
-   "b274e90b9e7f2f4ecff5d259d7b9d764e81a258d",
+   "f8db144cfe69ba23452da6aeffdd9c71d8696491",
    "support"
   ],
   "mathml/presentation-markup/fractions/frac-created-dynamically-3.html": [
-   "d5079473b757dc2fffae1f3851c4b2b9a299c89c",
+   "cec71163c392ebc6891339f8f1d80bad8c3f2596",
    "reftest"
   ],
   "mathml/presentation-markup/fractions/frac-created-dynamically-ref.html": [
@@ -631324,7 +631433,7 @@
    "support"
   ],
   "mathml/presentation-markup/fractions/frac-created-dynamically.html": [
-   "f6c2f2e4324becfc1730d97348e6ddd6f59b1086",
+   "3224eb4eaf188c32d6152339d86a87aa03cfa62e",
    "reftest"
   ],
   "mathml/presentation-markup/fractions/frac-linethickness-001-ref.html": [
@@ -631403,6 +631512,38 @@
    "c88484b9d59a7811f6cfde7065de4facbdf1f74a",
    "testharness"
   ],
+  "mathml/presentation-markup/operators/mo-form-dynamic-ref.html": [
+   "8f8d3da2c37cb5710d3758b0c6dfb7d2641a07bf",
+   "support"
+  ],
+  "mathml/presentation-markup/operators/mo-form-dynamic.html": [
+   "dcd1ec53c31efb2435415e372786e7a1fae15775",
+   "reftest"
+  ],
+  "mathml/presentation-markup/operators/mo-form-fallback-ref.html": [
+   "8d964eba45d6c09c53e61460baed76aced2e87b9",
+   "support"
+  ],
+  "mathml/presentation-markup/operators/mo-form-fallback.html": [
+   "aab62087b595a5f784c0b98e6a6cd0e419ac3a17",
+   "reftest"
+  ],
+  "mathml/presentation-markup/operators/mo-form-minus-plus-ref.html": [
+   "f83033373042444e28c26fc03c5f4acf38da131c",
+   "support"
+  ],
+  "mathml/presentation-markup/operators/mo-form-minus-plus.html": [
+   "8a4ac3d737315cca5c2ad19a95e60146bd633cf1",
+   "reftest"
+  ],
+  "mathml/presentation-markup/operators/mo-form-ref.html": [
+   "d48bd48a6e4a492e7fc31ae83d016cd12b9c8d56",
+   "support"
+  ],
+  "mathml/presentation-markup/operators/mo-form.html": [
+   "7c11c14691162b69c1a2e854734ae6ac37db10e2",
+   "reftest"
+  ],
   "mathml/presentation-markup/operators/mo-paint-lspace-rspace-ref.html": [
    "da0b79ff9a67cbe53daeb141aaa2efd4f2eb96ad",
    "support"
@@ -654663,16 +654804,16 @@
    "abfa4ab800b3c8e6b5f6fd3b42a982cc2e4fe99e",
    "support"
   ],
-  "resources/test/tests/unit/META.yml": [
-   "cb9e3f87620a634a3e9e92ac788a62751b061aa5",
-   "support"
-  ],
   "resources/test/tests/unit/basic.html": [
    "7eef4a8fa5b50547bce915170a9b3e1e0312adf4",
    "support"
   ],
+  "resources/test/tests/unit/exceptional-cases-timeouts.html": [
+   "760ac7154f1e6da3d072e77c9f10dca3c61d996f",
+   "support"
+  ],
   "resources/test/tests/unit/exceptional-cases.html": [
-   "1a5335f6c1f7f255388631a10ba561efe07c0afc",
+   "ef8f91bc61fac62f311e55cbd5c4d184af0c64ad",
    "support"
   ],
   "resources/test/tests/unit/late-test.html": [
@@ -657688,7 +657829,7 @@
    "testharness"
   ],
   "service-workers/service-worker/ready.https.html": [
-   "ff5c793f2c2208e9ac298e6b82adf745ae4c65e9",
+   "6c1ed822a8778c84ff151a680ed0b4c4fbdb53ca",
    "testharness"
   ],
   "service-workers/service-worker/redirected-response.https.html": [
@@ -657724,7 +657865,7 @@
    "testharness"
   ],
   "service-workers/service-worker/registration-end-to-end.https.html": [
-   "e92b6502f09b1a9308b96e43c6dc95f825fac692",
+   "1af4582d387412f47d82a94b2fe7050a5994644a",
    "testharness"
   ],
   "service-workers/service-worker/registration-events.https.html": [
@@ -661167,6 +661308,10 @@
    "c1d2b3a7e92a6f13192ecac29f52c8ccd7b3dd45",
    "testharness"
   ],
+  "svg/extensibility/foreignObject/foreign-object-under-defs-crash.html": [
+   "08c47454b6cb46887f6ab91c0e031d729538c572",
+   "testharness"
+  ],
   "svg/extensibility/foreignObject/position-svg-root-in-foreign-object-ref.html": [
    "668eb9b8c7e469540219b5ea9010db28239ae432",
    "support"
@@ -665112,7 +665257,7 @@
    "support"
   ],
   "tools/ci/azure/cleanup_win10.yml": [
-   "ba08b7eafabfb1bd03e8cbb8b421a6e85ed5960a",
+   "4abb35369de019c458ca6a5bae4a865363336810",
    "support"
   ],
   "tools/ci/azure/fyi_hook.yml": [
@@ -665127,6 +665272,10 @@
    "6bd5c2334ad4e3e4d5d6faaf8005f4e0b44cf1fe",
    "support"
   ],
+  "tools/ci/azure/install_edge.yml": [
+   "a70dc78e01c7c32c2eb04ae63eff70e4c982dd98",
+   "support"
+  ],
   "tools/ci/azure/install_firefox.yml": [
    "de6d0335f221f6d2215ebdc8ef5d2ee269fdfdf3",
    "support"
@@ -665140,7 +665289,7 @@
    "support"
   ],
   "tools/ci/azure/install_safari.yml": [
-   "be18f8376467b516a68e026c493b8fb679697236",
+   "bfb6afc332b1b85d7c322e19066708f034e9ac77",
    "support"
   ],
   "tools/ci/azure/pip_install.yml": [
@@ -669964,7 +670113,7 @@
    "support"
   ],
   "tools/wpt/browser.py": [
-   "e2c9341bd6756d93f8698dff5bae46fcf8c1f138",
+   "b093600b596fa8d3736b72e842bcbacdd82f6463",
    "support"
   ],
   "tools/wpt/commands.json": [
@@ -669992,7 +670141,7 @@
    "support"
   ],
   "tools/wpt/run.py": [
-   "07376797f589da8bd2a6c58708fa955a2702067f",
+   "0d7fa2233d64a6b5ee942038bc9a81ca33304938",
    "support"
   ],
   "tools/wpt/testfiles.py": [
diff --git a/tests/wpt/metadata/css/css-text-decor/text-decoration-width-computed.html.ini b/tests/wpt/metadata/css/css-text-decor/text-decoration-width-computed.html.ini
new file mode 100644
index 00000000000..ee5063099de
--- /dev/null
+++ b/tests/wpt/metadata/css/css-text-decor/text-decoration-width-computed.html.ini
@@ -0,0 +1,10 @@
+[text-decoration-width-computed.html]
+  [Property text-decoration-width value 'auto' computes to 'auto']
+    expected: FAIL
+
+  [Property text-decoration-width value 'calc(10px - 8px)' computes to '2px']
+    expected: FAIL
+
+  [Property text-decoration-width value 'from-font' computes to 'from-font']
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-text-decor/text-decoration-width-initial.html.ini b/tests/wpt/metadata/css/css-text-decor/text-decoration-width-initial.html.ini
new file mode 100644
index 00000000000..a381e0cab07
--- /dev/null
+++ b/tests/wpt/metadata/css/css-text-decor/text-decoration-width-initial.html.ini
@@ -0,0 +1,4 @@
+[text-decoration-width-initial.html]
+  [Initial value of text-decoration-width should be auto]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-text-decor/text-decoration-width-valid.html.ini b/tests/wpt/metadata/css/css-text-decor/text-decoration-width-valid.html.ini
new file mode 100644
index 00000000000..47c12636169
--- /dev/null
+++ b/tests/wpt/metadata/css/css-text-decor/text-decoration-width-valid.html.ini
@@ -0,0 +1,25 @@
+[text-decoration-width-valid.html]
+  [e.style['text-decoration-width'\] = "from-font" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "53px" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "2001em" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "-49em" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "calc(40em - 10px)" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "auto" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "calc(-50em + 13px)" should set the property value]
+    expected: FAIL
+
+  [e.style['text-decoration-width'\] = "-10px" should set the property value]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-ui/appearance-cssom-001.html.ini b/tests/wpt/metadata/css/css-ui/appearance-cssom-001.html.ini
index 5a23a5ee85d..ba8651527af 100644
--- a/tests/wpt/metadata/css/css-ui/appearance-cssom-001.html.ini
+++ b/tests/wpt/metadata/css/css-ui/appearance-cssom-001.html.ini
@@ -983,3 +983,27 @@
   [-webkit-appearance: scale-horizontal (invalid)]
     expected: FAIL
 
+  [appearance: menulist-text (invalid)]
+    expected: FAIL
+
+  [-webkit-appearance: menulist-textfield (invalid)]
+    expected: FAIL
+
+  [-webkit-appearance: menulist-text (invalid)]
+    expected: FAIL
+
+  [-webkit-appearance: caret (invalid)]
+    expected: FAIL
+
+  [appearance: caret (invalid)]
+    expected: FAIL
+
+  [-webkit-appearance: button-bevel (invalid)]
+    expected: FAIL
+
+  [appearance: menulist-textfield (invalid)]
+    expected: FAIL
+
+  [appearance: button-bevel (invalid)]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/css/css-values/vh_not_refreshing_on_chrome.html.ini b/tests/wpt/metadata/css/css-values/vh_not_refreshing_on_chrome.html.ini
index d708d05b3ca..6c46d48c239 100644
--- a/tests/wpt/metadata/css/css-values/vh_not_refreshing_on_chrome.html.ini
+++ b/tests/wpt/metadata/css/css-values/vh_not_refreshing_on_chrome.html.ini
@@ -1,3 +1,3 @@
 [vh_not_refreshing_on_chrome.html]
   bug: https://github.com/servo/servo/issues/8984
-  expected: CRASH
+  expected: TIMEOUT
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
deleted file mode 100644
index e6e1f29e274..00000000000
--- a/tests/wpt/metadata/css/cssom-view/matchMedia-display-none-iframe.html.ini
+++ /dev/null
@@ -1,2 +0,0 @@
-[matchMedia-display-none-iframe.html]
-  expected: ERROR
diff --git a/tests/wpt/metadata/fetch/api/request/destination/fetch-destination-worker.https.html.ini b/tests/wpt/metadata/fetch/api/request/destination/fetch-destination-worker.https.html.ini
index e37a60085bb..652ea61023a 100644
--- a/tests/wpt/metadata/fetch/api/request/destination/fetch-destination-worker.https.html.ini
+++ b/tests/wpt/metadata/fetch/api/request/destination/fetch-destination-worker.https.html.ini
@@ -1,8 +1,16 @@
 [fetch-destination-worker.https.html]
   [Fetch destination tests for resources with no load event]
     expected: FAIL
+
   [Initialize global state]
     expected: FAIL
+
   [Worker fetches with a "worker" Request.destination]
     expected: FAIL
- 
+
+  [DedicatedWorker fetches with a "worker" Request.destination]
+    expected: FAIL
+
+  [SharedWorker fetches with a "sharedworker" Request.destination]
+    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 d42cf41a720..fd5d7772285 100644
--- a/tests/wpt/metadata/fetch/content-type/response.window.js.ini
+++ b/tests/wpt/metadata/fetch/content-type/response.window.js.ini
@@ -312,27 +312,21 @@
   [<iframe>: separate response Content-Type: text/plain */*;charset=gbk]
     expected: FAIL
 
-  [<iframe>: combined response Content-Type: text/html */*;charset=gbk]
-    expected: FAIL
-
-  [<iframe>: combined response Content-Type: */* text/html]
-    expected: FAIL
-
   [<iframe>: combined response Content-Type: text/html;x=" text/plain]
     expected: FAIL
 
   [<iframe>: combined response Content-Type: text/html;charset=gbk text/plain text/html]
     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 */*]
+  [<iframe>: separate response Content-Type: text/html;charset=gbk text/plain text/html]
     expected: FAIL
 
-  [<iframe>: separate response Content-Type: text/html;" \\" text/plain]
+  [<iframe>: separate response Content-Type: */* text/html]
+    expected: FAIL
+
+  [<iframe>: separate response Content-Type: text/html;x=" text/plain]
     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 87c807a49ff..a63e414f43a 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%0C]
     expected: FAIL
 
+  [X-Content-Type-Options%3A%20%40%23%24%23%25%25%26%5E%26%5E*()()11!%2Cnosniff]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
new file mode 100644
index 00000000000..75d75b4cda2
--- /dev/null
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_2.html.ini
@@ -0,0 +1,4 @@
+[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_4.html.ini b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
new file mode 100644
index 00000000000..385376c7321
--- /dev/null
+++ b/tests/wpt/metadata/html/browsers/history/the-history-interface/traverse_the_history_4.html.ini
@@ -0,0 +1,4 @@
+[traverse_the_history_4.html]
+  [Multiple history traversals, last would be aborted]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini
index bf50d59df41..e02f179ec25 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-innerwidth-innerheight.html.ini
@@ -1,5 +1,24 @@
 [open-features-negative-innerwidth-innerheight.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: negative values for legacy `innerwidth`, `innerheight`]
     expected: FAIL
 
+  [features "innerheight=-404.5" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=-404.5" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=-404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "innerheight=-404e1" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerheight=-404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=-404e1" should NOT set "width=404"]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-screenx-screeny.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-screenx-screeny.html.ini
index e150c9d848f..23eefb8eaf9 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-screenx-screeny.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-screenx-screeny.html.ini
@@ -1,5 +1,24 @@
 [open-features-negative-screenx-screeny.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: negative values for legacy `screenx`, `screeny`]
     expected: FAIL
 
+  [features "screenx=-204" should NOT set "left=204"]
+    expected: TIMEOUT
+
+  [features "screeny=-204" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "screeny=-204.5" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "screeny=-0" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "screenx=-0" should NOT set "left=204"]
+    expected: TIMEOUT
+
+  [features "screenx=-204.5" should NOT set "left=204"]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini
index ad8840fbb68..940516ddd33 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-top-left.html.ini
@@ -1,5 +1,24 @@
 [open-features-negative-top-left.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: negative values for `top`, `left`]
     expected: FAIL
 
+  [features "top=-204" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "top=-204.5" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "left=-204" should NOT set "left=204"]
+    expected: TIMEOUT
+
+  [features "top=-0" should NOT set "top=204"]
+    expected: TIMEOUT
+
+  [features "left=-204.5" should NOT set "left=204"]
+    expected: TIMEOUT
+
+  [features "left=-0" should NOT set "left=204"]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini
index d1ed9088b2b..9027336b453 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-negative-width-height.html.ini
@@ -1,5 +1,24 @@
 [open-features-negative-width-height.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: negative values for `width`, `height`]
     expected: FAIL
 
+  [features "height=-404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "height=-404e1" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "height=-404.5" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "width=-404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "width=-404e1" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "width=-404.5" should NOT set "width=404"]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-height.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-height.html.ini
index a70e9dbad4d..4e44584b123 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-height.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-height.html.ini
@@ -1,32 +1,48 @@
 [open-features-non-integer-height.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for feature `height`]
     expected: FAIL
 
   [features "height=405*3" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405.32" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405e1" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405/5" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405^4" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405.5" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405e-1" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405  " should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "height=405LLl" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "height=/404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [top=0,left=0,width=401,: absence of feature "height" should be treated same as "height=0"]
+    expected: TIMEOUT
+
+  [top=0,left=0: absence of feature "height" should be treated same as "height=0"]
+    expected: TIMEOUT
+
+  [features "height=_404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "height=L404" should NOT set "height=404"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerheight.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerheight.html.ini
index 779531b4a98..fcaeae5336d 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerheight.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerheight.html.ini
@@ -1,32 +1,42 @@
 [open-features-non-integer-innerheight.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for legacy feature `innerheight`]
     expected: FAIL
 
   [features "innerheight=405e-1" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405LLl" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405^4" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405e1" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405  " should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405/5" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405.32" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405.5" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerheight=405*3" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "innerheight=_404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerheight=L404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "innerheight=/404" should NOT set "height=404"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerwidth.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerwidth.html.ini
index 7a1b258d52e..42327fedd27 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerwidth.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-innerwidth.html.ini
@@ -1,32 +1,42 @@
 [open-features-non-integer-innerwidth.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for legacy feature `innerwidth`]
     expected: FAIL
 
   [features "innerwidth=405e-1" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405*3" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405.5" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405e1" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405.32" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405  " should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405LLl" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405/5" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "innerwidth=405^4" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "innerwidth=/404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=_404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "innerwidth=L404" should NOT set "width=404"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-left.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-left.html.ini
index caba4124f0b..a8e4fe06618 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-left.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-left.html.ini
@@ -1,32 +1,42 @@
 [open-features-non-integer-left.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for feature `left`]
     expected: FAIL
 
   [features "left=105e1" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105  " should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105/5" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105e-1" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105^4" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105LLl" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105.32" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105*3" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "left=105.5" should set "left=105"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "left=L104" should NOT set "left=104"]
+    expected: TIMEOUT
+
+  [features "left=/104" should NOT set "left=104"]
+    expected: TIMEOUT
+
+  [features "left=_104" should NOT set "left=104"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-screeny.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-screeny.html.ini
index a82bd0f981a..4f22ef4ef29 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-screeny.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-screeny.html.ini
@@ -1,32 +1,42 @@
 [open-features-non-integer-screeny.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for legacy feature `screeny`]
     expected: FAIL
 
   [features "screeny=405^4" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405e-1" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405LLl" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405e1" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405  " should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405/5" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405*3" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405.32" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "screeny=405.5" should set "height=405"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "screeny=_404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "screeny=L404" should NOT set "height=404"]
+    expected: TIMEOUT
+
+  [features "screeny=/404" should NOT set "height=404"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini
index 10f617db69e..8540f53d8d6 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-top.html.ini
@@ -1,32 +1,42 @@
 [open-features-non-integer-top.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for feature `top`]
     expected: FAIL
 
   [features "top=105/5" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105*3" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105LLl" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105e-1" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105.32" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105e1" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105  " should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105^4" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "top=105.5" should set "top=105"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [features "top=/104" should NOT set "top=104"]
+    expected: TIMEOUT
+
+  [features "top=_104" should NOT set "top=104"]
+    expected: TIMEOUT
+
+  [features "top=L104" should NOT set "top=104"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini
index 28f93ee71b5..9d841e61bc0 100644
--- a/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini
+++ b/tests/wpt/metadata/html/browsers/the-window-object/apis-for-creating-and-navigating-browsing-contexts-by-name/open-features-non-integer-width.html.ini
@@ -1,32 +1,48 @@
 [open-features-non-integer-width.html]
   type: testharness
+  expected: TIMEOUT
   [HTML: window.open `features`: non-integer values for feature `width`]
     expected: FAIL
 
   [features "width=405^4" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405.5" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405e1" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405  " should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405.32" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405LLl" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405*3" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405e-1" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
 
   [features "width=405/5" should set "width=405"]
-    expected: FAIL
+    expected: TIMEOUT
+
+  [top=0,left=0: absence of feature "width" should be treated same as "width=0"]
+    expected: TIMEOUT
+
+  [features "width=_404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [top=0,left=0,height=401,: absence of feature "width" should be treated same as "width=0"]
+    expected: TIMEOUT
+
+  [features "width=/404" should NOT set "width=404"]
+    expected: TIMEOUT
+
+  [features "width=L404" should NOT set "width=404"]
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
new file mode 100644
index 00000000000..8cc42056d34
--- /dev/null
+++ b/tests/wpt/metadata/html/semantics/embedded-content/the-img-element/non-active-document.html.ini
@@ -0,0 +1,10 @@
+[non-active-document.html]
+  [DOMParser]
+    expected: FAIL
+
+  [createHTMLDocument]
+    expected: FAIL
+
+  [<template>]
+    expected: FAIL
+
diff --git a/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events.html.ini b/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events.html.ini
index 496bad988c6..034d9baebfa 100644
--- a/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events.html.ini
+++ b/tests/wpt/metadata/html/webappapis/scripting/processing-model-2/unhandled-promise-rejections/promise-rejection-events.html.ini
@@ -1,4 +1,5 @@
 [promise-rejection-events.html]
+  expected: TIMEOUT
   [delayed handling: delaying handling rejected promise created from createImageBitmap will cause both events to fire]
     expected: FAIL
 
@@ -8,3 +9,6 @@
   [no unhandledrejection/rejectionhandled: rejection handler attached synchronously to a promise created from createImageBitmap]
     expected: FAIL
 
+  [rejectionhandled is dispatched from a queued task, and not immediately]
+    expected: TIMEOUT
+
diff --git a/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini b/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini
index 66bd350083b..a56bad443a2 100644
--- a/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini
+++ b/tests/wpt/metadata/webaudio/the-audio-api/the-analysernode-interface/realtimeanalyser-fft-scaling.html.ini
@@ -1,4 +1,5 @@
 [realtimeanalyser-fft-scaling.html]
+  expected: TIMEOUT
   [X 2048-point FFT peak position is not equal to 64. Got 0.]
     expected: FAIL
 
diff --git a/tests/wpt/web-platform-tests/.azure-pipelines.yml b/tests/wpt/web-platform-tests/.azure-pipelines.yml
index 99873aece5c..72a509e6b19 100644
--- a/tests/wpt/web-platform-tests/.azure-pipelines.yml
+++ b/tests/wpt/web-platform-tests/.azure-pipelines.yml
@@ -220,10 +220,11 @@ jobs:
     parameters:
       packages: virtualenv
   - template: tools/ci/azure/install_certs.yml
+  - template: tools/ci/azure/install_edge.yml
   - template: tools/ci/azure/update_hosts.yml
   - template: tools/ci/azure/update_manifest.yml
-  - script: python ./wpt run --yes --no-manifest-update --install-fonts --manifest MANIFEST.json --metadata infrastructure/metadata/ --webdriver-arg=--verbose --log-tbpl $(Build.ArtifactStagingDirectory)/edge.tbpl.log --log-tbpl-level info edge_webdriver infrastructure/
-    displayName: 'Run tests (Edge)'
+  - script: python ./wpt run --yes --no-manifest-update --install-fonts --manifest MANIFEST.json --metadata infrastructure/metadata/ --log-tbpl $(Build.ArtifactStagingDirectory)/edge.tbpl.log --log-tbpl-level info --channel dev edgechromium infrastructure/
+    displayName: 'Run tests (Edge Dev)'
   - task: PublishBuildArtifacts@1
     displayName: 'Publish results'
     inputs:
@@ -252,10 +253,11 @@ jobs:
     parameters:
       packages: virtualenv
   - template: tools/ci/azure/install_certs.yml
+  - template: tools/ci/azure/install_edge.yml
   - template: tools/ci/azure/update_hosts.yml
   - template: tools/ci/azure/update_manifest.yml
-  - script: python ./wpt run --no-manifest-update --no-restart-on-unexpected --no-fail-on-unexpected --install-fonts --webdriver-arg=--verbose --test-types reftest testharness --this-chunk $(System.JobPositionInPhase) --total-chunks $(System.TotalJobsInPhase) --chunk-type hash --log-tbpl - --log-tbpl-level info --log-wptreport $(Build.ArtifactStagingDirectory)/wpt_report_$(System.JobPositionInPhase).json --log-wptscreenshot $(Build.ArtifactStagingDirectory)/wpt_screenshot_$(System.JobPositionInPhase).txt edge_webdriver
-    displayName: 'Run tests'
+  - script: python ./wpt run --yes --no-manifest-update --no-restart-on-unexpected --no-fail-on-unexpected --install-fonts --this-chunk $(System.JobPositionInPhase) --total-chunks $(System.TotalJobsInPhase) --chunk-type hash --log-tbpl - --log-tbpl-level info --log-wptreport $(Build.ArtifactStagingDirectory)/wpt_report_$(System.JobPositionInPhase).json --log-wptscreenshot $(Build.ArtifactStagingDirectory)/wpt_screenshot_$(System.JobPositionInPhase).txt edgechromium
+    displayName: 'Run tests (Edge Dev)'
   - task: PublishBuildArtifacts@1
     displayName: 'Publish results'
     inputs:
diff --git a/tests/wpt/web-platform-tests/WebIDL/META.yml b/tests/wpt/web-platform-tests/WebIDL/META.yml
index a8dc9c4410e..6aaee0e2694 100644
--- a/tests/wpt/web-platform-tests/WebIDL/META.yml
+++ b/tests/wpt/web-platform-tests/WebIDL/META.yml
@@ -1,5 +1,4 @@
 spec: https://heycam.github.io/webidl/
 suggested_reviewers:
   - domenic
-  - tobie
   - yuki3
diff --git a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-computed.html b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-computed.html
new file mode 100644
index 00000000000..0e00240141e
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-computed.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text Decoration Test: parsing text-decoration-width computed values</title>
+<link rel="help" href="https://drafts.csswg.org/css-text-decor-4/#text-decoration-width-property">
+<meta name="assert" content="text-decoration-width computed value is as specified.">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/computed-testcommon.js"></script>
+</head>
+<body>
+<div id="target"></div>
+<script>
+test_computed_value("text-decoration-width", "auto");
+test_computed_value("text-decoration-width", "from-font");
+test_computed_value("text-decoration-width", "calc(10px - 8px)", "2px");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-initial.html b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-initial.html
new file mode 100644
index 00000000000..ee47af0f115
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-initial.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<link rel="help" title="2.4 Text Decoration Width: the 'text-decoration-width' property"
+      href="https://drafts.csswg.org/css-text-decor-4/#text-decoration-width-property" />
+</head>
+<body>
+<script>
+test(function() {
+  assert_equals(getComputedStyle(document.body)["text-decoration-width"], "auto", "Must be set to value auto as initial value.");
+}, "Initial value of text-decoration-width should be auto");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-invalid.html b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-invalid.html
new file mode 100644
index 00000000000..e89fe47ff2d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-invalid.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text Decoration Test: parsing text-decoration-width with invalid values</title>
+<link rel="help" href="https://drafts.csswg.org/css-text-decor-4/#text-decoration-width-property">
+<meta name="assert" content="text-decoration-width supports the following values: auto | from-font | <length>">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+test_invalid_value("text-decoration-width", "otto");
+test_invalid_value("text-decoration-width", "asdlflj");
+test_invalid_value("text-decoration-width", "-10");
+test_invalid_value("text-decoration-width", "60002020");
+test_invalid_value("text-decoration-width", "!@#$%^&");
+test_invalid_value("text-decoration-width", "10e2");
+test_invalid_value("text-decoration-width", "from font");
+test_invalid_value("text-decoration-width", "10%");
+test_invalid_value("text-decoration-width", "-27%");
+test_invalid_value("text-decoration-width", "calc(40% - 20px)");
+test_invalid_value("text-decoration-width", "calc(100% - 40em)");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-valid.html b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-valid.html
new file mode 100644
index 00000000000..583ebb0d3cf
--- /dev/null
+++ b/tests/wpt/web-platform-tests/css/css-text-decor/text-decoration-width-valid.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<html>
+<head>
+<meta charset="utf-8">
+<title>CSS Text Decoration Test: parsing text-decoration-width longhands with valid values</title>
+<link rel="help" href="https://drafts.csswg.org/css-text-decor-4/#text-decoration-width-property">
+<meta name="assert" content="text-decoration-width supports the following values: auto | from-font | <length>">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+</head>
+<body>
+<script>
+test_valid_value("text-decoration-width", "auto");
+test_valid_value("text-decoration-width", "from-font");
+test_valid_value("text-decoration-width", "-10px");
+test_valid_value("text-decoration-width", "2001em");
+test_valid_value("text-decoration-width", "-49em");
+test_valid_value("text-decoration-width", "53px");
+test_valid_value("text-decoration-width", "calc(40em - 10px)");
+test_valid_value("text-decoration-width", "calc(-50em + 13px)");
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/animation-timing-function.html b/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/animation-timing-function.html
index b66d64c9b9a..eb9af36a85a 100644
--- a/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/animation-timing-function.html
+++ b/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/animation-timing-function.html
@@ -19,8 +19,18 @@ runListValuedPropertyTests('animation-timing-function', [
   { syntax: 'ease-in' },
   { syntax: 'ease-out' },
   { syntax: 'ease-in-out' },
-  { syntax: 'step-start' },
-  { syntax: 'step-end' },
+  {
+    syntax: 'step-start',
+    computed: (_, result) => {
+      assert_equals(result.toString(), 'steps(1, start)');
+    }
+  },
+  {
+    syntax: 'step-end',
+    computed: (_, result) => {
+      assert_equals(result.toString(), 'steps(1)');
+    }
+  },
 ]);
 
 runUnsupportedPropertyTests('animation-timing-function', [
diff --git a/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/transition-timing-function.html b/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/transition-timing-function.html
index 5d3260f7a51..a4dbfc19330 100644
--- a/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/transition-timing-function.html
+++ b/tests/wpt/web-platform-tests/css/css-typed-om/the-stylepropertymap/properties/transition-timing-function.html
@@ -19,8 +19,18 @@ runListValuedPropertyTests('transition-timing-function', [
   { syntax: 'ease-in' },
   { syntax: 'ease-out' },
   { syntax: 'ease-in-out' },
-  { syntax: 'step-start' },
-  { syntax: 'step-end' },
+  {
+    syntax: 'step-start',
+    computed: (_, result) => {
+      assert_equals(result.toString(), 'steps(1, start)');
+    }
+  },
+  {
+    syntax: 'step-end',
+    computed: (_, result) => {
+      assert_equals(result.toString(), 'steps(1)');
+    }
+  },
 ]);
 
 runUnsupportedPropertyTests('transition-timing-function', [
diff --git a/tests/wpt/web-platform-tests/css/css-ui/appearance-cssom-001.html b/tests/wpt/web-platform-tests/css/css-ui/appearance-cssom-001.html
index 2d439ba615f..f7dd4d1d761 100644
--- a/tests/wpt/web-platform-tests/css/css-ui/appearance-cssom-001.html
+++ b/tests/wpt/web-platform-tests/css/css-ui/appearance-cssom-001.html
@@ -10,15 +10,10 @@
   const values = ["none",
                   "auto",
                   "button",
-                  "button-bevel",
-                  "caret",
                   "checkbox",
                   "listbox",
-                  "listitem",
                   "menulist",
                   "menulist-button",
-                  "menulist-text",
-                  "menulist-textfield",
                   "meter",
                   "progress-bar",
                   "push-button",
@@ -51,6 +46,7 @@
 
     const invalidValues = ["bogus-button",
                            "attachment",
+                           "button-bevel",
                            "borderless-attachment",
                            "button-arrow-down",
                            "button-arrow-next",
@@ -58,6 +54,7 @@
                            "button-arrow-up",
                            "button-focus",
                            "caps-lock-indicator",
+                           "caret",
                            "checkbox-container",
                            "checkbox-label",
                            "checkmenuitem",
@@ -67,40 +64,42 @@
                            "discrete-capacity-level-indicator",
                            "dualbutton",
                            "groupbox",
-                           "inner-spin-button",
                            "image-controls-button",
+                           "inner-spin-button",
                            "list-button",
                            "listitem",
-                           "media-enter-fullscreen-button",
-                           "media-exit-fullscreen-button",
-                           "media-fullscreen-volume-slider",
-                           "media-fullscreen-volume-slider-thumb",
-                           "media-mute-button",
-                           "media-play-button",
-                           "media-overlay-play-button",
-                           "media-return-to-realtime-button",
-                           "media-rewind-button",
-                           "media-seek-back-button",
-                           "media-seek-forward-button",
-                           "media-toggle-closed-captions-button",
-                           "media-slider",
-                           "media-sliderthumb",
-                           "media-volume-slider-container",
-                           "media-volume-slider-mute-button",
-                           "media-volume-slider",
-                           "media-volume-sliderthumb",
                            "media-controls-background",
                            "media-controls-dark-bar-background",
                            "media-controls-fullscreen-background",
                            "media-controls-light-bar-background",
                            "media-current-time-display",
+                           "media-enter-fullscreen-button",
+                           "media-exit-fullscreen-button",
+                           "media-fullscreen-volume-slider",
+                           "media-fullscreen-volume-slider-thumb",
+                           "media-mute-button",
+                           "media-overlay-play-button",
+                           "media-play-button",
+                           "media-return-to-realtime-button",
+                           "media-rewind-button",
+                           "media-seek-back-button",
+                           "media-seek-forward-button",
+                           "media-slider",
+                           "media-sliderthumb",
                            "media-time-remaining-display",
+                           "media-toggle-closed-captions-button",
+                           "media-volume-slider",
+                           "media-volume-slider-container",
+                           "media-volume-slider-mute-button",
+                           "media-volume-sliderthumb",
                            "menuarrow",
                            "menubar",
                            "menucheckbox",
                            "menuimage",
                            "menuitem",
                            "menuitemtext",
+                           "menulist-text",
+                           "menulist-textfield",
                            "menupopup",
                            "menuradio",
                            "menuseparator",
@@ -118,15 +117,16 @@
                            "range",
                            "range-thumb",
                            "rating-level-indicator",
+                           "relevancy-level-indicator",
                            "resizer",
                            "resizerpanel",
                            "scale-horizontal",
-                           "scalethumbend",
+                           "scale-vertical",
                            "scalethumb-horizontal",
+                           "scalethumb-vertical",
+                           "scalethumbend",
                            "scalethumbstart",
                            "scalethumbtick",
-                           "scalethumb-vertical",
-                           "scale-vertical",
                            "scrollbarbutton-down",
                            "scrollbarbutton-left",
                            "scrollbarbutton-right",
@@ -135,16 +135,16 @@
                            "scrollbarthumb-vertical",
                            "scrollbartrack-horizontal",
                            "scrollbartrack-vertical",
-                           "searchfield-decoration",
-                           "searchfield-results-decoration",
-                           "searchfield-results-button",
                            "searchfield-cancel-button",
-                           "snapshotted-plugin-overlay",
+                           "searchfield-decoration",
+                           "searchfield-results-button",
+                           "searchfield-results-decoration",
                            "separator",
                            "sheet",
                            "slider-vertical",
                            "sliderthumb-horizontal",
                            "sliderthumb-vertical",
+                           "snapshotted-plugin-overlay",
                            "spinner",
                            "spinner-downbutton",
                            "spinner-textfield",
@@ -153,10 +153,10 @@
                            "statusbar",
                            "statusbarpanel",
                            "tab",
-                           "tabpanel",
-                           "tabpanels",
                            "tab-scroll-arrow-back",
                            "tab-scroll-arrow-forward ",
+                           "tabpanel",
+                           "tabpanels",
                            "textfield-multiline",
                            "toolbar",
                            "toolbarbutton",
@@ -172,11 +172,11 @@
                            "treetwisty",
                            "treetwistyopen",
                            "treeview",
-                           "relevancy-level-indicator",
+                           "-apple-pay-button",
                            "-moz-win-borderless-glass",
                            "-moz-win-browsertabbar-toolbox",
-                           "-moz-win-communicationstext",
                            "-moz-win-communications-toolbox",
+                           "-moz-win-communicationstext",
                            "-moz-win-exclude-glass",
                            "-moz-win-glass",
                            "-moz-win-media-toolbox",
@@ -191,7 +191,6 @@
                            "-moz-window-frame-right",
                            "-moz-window-titlebar",
                            "-moz-window-titlebar-maximized",
-                           "-apple-pay-button",
                            ];
     for (const invalidValue of invalidValues) {
       test(() => {
diff --git a/tests/wpt/web-platform-tests/fetch/api/request/destination/fetch-destination-worker.https.html b/tests/wpt/web-platform-tests/fetch/api/request/destination/fetch-destination-worker.https.html
index 8421d4ac9ef..5935c1ff31e 100644
--- a/tests/wpt/web-platform-tests/fetch/api/request/destination/fetch-destination-worker.https.html
+++ b/tests/wpt/web-platform-tests/fetch/api/request/destination/fetch-destination-worker.https.html
@@ -46,9 +46,15 @@ var waitOnMessageFromSW = async t => {
 // worker destination
 /////////////////////
 promise_test(async t => {
-    // We can use an html file as we don't really care about the worker successfully loading.
+    // We can use an html file as we don't really care about the dedicated worker successfully loading.
     let worker = new frame.contentWindow.Worker("dummy.html?t=worker&dest=worker");
     await waitOnMessageFromSW(t);
-}, 'Worker fetches with a "worker" Request.destination');
+}, 'DedicatedWorker fetches with a "worker" Request.destination');
+
+promise_test(async t => {
+    // We can use an html file as we don't really care about the shared worker successfully loading.
+    let worker = new frame.contentWindow.SharedWorker("dummy.html?t=sharedworker&dest=sharedworker");
+    await waitOnMessageFromSW(t);
+}, 'SharedWorker fetches with a "sharedworker" Request.destination');
 
 </script>
diff --git a/tests/wpt/web-platform-tests/interfaces/webxr.idl b/tests/wpt/web-platform-tests/interfaces/webxr.idl
index 63327a3f55d..9b48a0f9040 100644
--- a/tests/wpt/web-platform-tests/interfaces/webxr.idl
+++ b/tests/wpt/web-platform-tests/interfaces/webxr.idl
@@ -126,7 +126,7 @@ enum XREye {
 interface XRRigidTransform {
   [SameObject] readonly attribute DOMPointReadOnly position;
   [SameObject] readonly attribute DOMPointReadOnly orientation;
-  [SameObject] readonly attribute Float32Array matrix;
+  readonly attribute Float32Array matrix;
   [SameObject] readonly attribute XRRigidTransform inverse;
 };
 
@@ -136,7 +136,7 @@ interface XRRigidTransform {
 interface XRRay {
   [SameObject] readonly attribute DOMPointReadOnly origin;
   [SameObject] readonly attribute DOMPointReadOnly direction;
-  [SameObject] readonly attribute Float32Array matrix;
+  readonly attribute Float32Array matrix;
 };
 
 [SecureContext, Exposed=Window] interface XRPose {
diff --git a/tests/wpt/web-platform-tests/lint.whitelist b/tests/wpt/web-platform-tests/lint.whitelist
index 04738ee9727..c788ddd5fd6 100644
--- a/tests/wpt/web-platform-tests/lint.whitelist
+++ b/tests/wpt/web-platform-tests/lint.whitelist
@@ -319,6 +319,7 @@ SET TIMEOUT: resources/test/tests/functional/api-tests-1.html
 SET TIMEOUT: resources/test/tests/functional/worker.js
 SET TIMEOUT: resources/test/tests/functional/worker-uncaught-allow.js
 SET TIMEOUT: resources/test/tests/unit/exceptional-cases.html
+SET TIMEOUT: resources/test/tests/unit/exceptional-cases-timeouts.html
 SET TIMEOUT: resources/testharness.js
 
 # setTimeout use in reftests
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-2.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-2.html
index 4c8b7e303bd..a9707071a06 100644
--- a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-2.html
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-2.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html class="reftest-wait">
 <head>
 <meta charset="utf-8">
 <title>mfrac created dynamically</title>
@@ -7,7 +7,11 @@
 <meta name="assert" content="A dynamically added mfrac should render like the equivalent markup.">
 <link rel="match" href="frac-created-dynamically-2-ref.html">
 <script>
-  window.addEventListener("DOMContentLoaded", function() {
+  window.addEventListener("load", function() {
+
+  // force initial layout so we're sure what we're testing against
+  document.documentElement.getBoundingClientRect();
+
   var mfrac = document.createElementNS("http://www.w3.org/1998/Math/MathML","mfrac");
   var mspace1 = document.createElementNS("http://www.w3.org/1998/Math/MathML","mspace");
   mspace1.setAttribute("width", "50px");
@@ -25,6 +29,8 @@
   mfrac.appendChild(mspace1);
   mfrac.appendChild(mspace2);
   mfrac.appendChild(mspace3);
+
+  document.documentElement.classList.remove('reftest-wait');
   });
 </script>
 </head>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3-ref.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3-ref.html
index b274e90b9e7..f8db144cfe6 100644
--- a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3-ref.html
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3-ref.html
@@ -8,8 +8,8 @@
     <p>This test passes if you see a fraction 1/3.</p>
     <math>
       <mfrac>
-        <mi>1</mi>
-        <mi>3</mi>
+        <mn>1</mn>
+        <mn>3</mn>
       </mfrac>
     </math>
   </body>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3.html
index d5079473b75..cec71163c39 100644
--- a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3.html
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically-3.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html class="reftest-wait">
 <head>
 <meta charset="utf-8">
 <title>mfrac created dynamically</title>
@@ -7,11 +7,17 @@
 <meta name="assert" content="A dynamically added mfrac should render like the equivalent markup.">
 <link rel="match" href="frac-created-dynamically-3-ref.html">
 <script>
-  window.addEventListener("DOMContentLoaded", function() {
-  var mi3 = document.createElementNS("http://www.w3.org/1998/Math/MathML","mi");
-  mi3.appendChild(document.createTextNode("3"));
-  document.getElementsByTagName("mfrac")[0].appendChild(mi3);
-  document.getElementById("mi2").remove();
+  window.addEventListener("load", function() {
+
+  // force initial layout so we're sure what we're testing against
+  document.documentElement.getBoundingClientRect();
+
+  var mn3 = document.createElementNS("http://www.w3.org/1998/Math/MathML","mn");
+  mn3.appendChild(document.createTextNode("3"));
+  document.getElementsByTagName("mfrac")[0].appendChild(mn3);
+  document.getElementById("mn2").remove();
+
+  document.documentElement.classList.remove('reftest-wait');
   });
 </script>
 </head>
@@ -19,8 +25,8 @@
   <p>This test passes if you see a fraction 1/3.</p>
   <math>
     <mfrac>
-      <mi>1</mi>
-      <mi id="mi2">2</mi>
+      <mn>1</mn>
+      <mn id="mn2">2</mn>
     </mfrac>
   </math>
 </body>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically.html
index f6c2f2e4324..3224eb4eaf1 100644
--- a/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically.html
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/fractions/frac-created-dynamically.html
@@ -1,5 +1,5 @@
 <!DOCTYPE html>
-<html>
+<html class="reftest-wait">
 <head>
 <meta charset="utf-8">
 <title>mfrac created dynamically</title>
@@ -7,7 +7,11 @@
 <meta name="assert" content="A dynamically added mfrac should render like the equivalent markup.">
 <link rel="match" href="frac-created-dynamically-ref.html">
 <script>
-  window.addEventListener("DOMContentLoaded", function() {
+  window.addEventListener("load", function() {
+
+  // force initial layout so we're sure what we're testing against
+  document.documentElement.getBoundingClientRect();
+
   var mfrac = document.createElementNS("http://www.w3.org/1998/Math/MathML","mfrac");
   var mspace1 = document.createElementNS("http://www.w3.org/1998/Math/MathML","mspace");
   mspace1.setAttribute("width", "50px");
@@ -20,6 +24,8 @@
   mfrac.appendChild(mspace1);
   mfrac.appendChild(mspace2);
   document.getElementsByTagName("math")[0].appendChild(mfrac);
+
+  document.documentElement.classList.remove('reftest-wait');
   });
 </script>
 </head>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-dynamic-ref.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-dynamic-ref.html
new file mode 100644
index 00000000000..8f8d3da2c37
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-dynamic-ref.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>&lt;mo&gt; dynamic form</title>
+  </head>
+  <body>
+
+    <p>The test should render the same as the static reference.</p>
+
+    _<math><merror><mi>x</mi><mo>+</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo>+</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo>+</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo>+</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo>+</mo><mi>y</mi></mstyle></math>_
+
+    _<math><merror><mo>−</mo><mi>y</mi></merror></math>_
+    _<math><mo>−</mo><mi>y</mi></math>_
+    _<math><mphantom><mo>−</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mo>−</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mo>−</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mo>−</mo><mi>y</mi></mstyle></math>_
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-dynamic.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-dynamic.html
new file mode 100644
index 00000000000..dcd1ec53c31
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-dynamic.html
@@ -0,0 +1,48 @@
+<!DOCTYPE html>
+<html class="reftest-wait">
+  <head>
+    <meta charset="utf-8"/>
+    <title>&lt;mo&gt; dynamic form</title>
+    <link rel="help" href="https://mathml-refresh.github.io/mathml-core/#tokenmo">
+    <meta name="assert" content="This test verifies that the form of the operators (and thus their spacing) is updated when you change the child list.">
+    <link rel="match" href="mo-form-dynamic-ref.html">
+
+    <script>
+      window.addEventListener("load", () => {
+
+        // force initial layout so we're sure what we're testing against
+        document.documentElement.getBoundingClientRect();
+
+        for (var i = 1; i <= 6; i++) {
+          var row = document.getElementById("row" + i);
+          var x = document.getElementById("x" + i);
+
+          x.parentNode.removeChild(x);
+
+          row.insertBefore(x, row.firstElementChild);
+        }
+
+        document.documentElement.classList.remove('reftest-wait');
+      })
+    </script>
+  </head>
+  <body>
+
+    <p>The test should render the same as the static reference.</p>
+
+    _<math><merror id="row1"><mo>+</mo><mi>y</mi></merror></math>_
+    _<math id="row2"><mo>+</mo><mi>y</mi></math>_
+    _<math><mphantom id="row3"><mo>+</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow id="row4"><mo>+</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt id="row5"><mo>+</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle id="row6"><mo>+</mo><mi>y</mi></mstyle></math>_
+
+    _<math><merror><mi id="x1">x</mi><mo>−</mo><mi>y</mi></merror></math>_
+    _<math><mi id="x2">x</mi><mo>−</mo><mi>y</mi></math>_
+    _<math><mphantom><mi id="x3">x</mi><mo>−</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi id="x4">x</mi><mo>−</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi id="x5">x</mi><mo>−</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi id="x6">x</mi><mo>−</mo><mi>y</mi></mstyle></math>_
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-fallback-ref.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-fallback-ref.html
new file mode 100644
index 00000000000..8d964eba45d
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-fallback-ref.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>form fallback</title>
+  </head>
+  <body>
+
+    <math>
+      <mo stretchy="true">(</mo> <mspace height="3em" depth="3em"/> <mo stretchy="true">)</mo>
+      <mo stretchy="true">(</mo> <mspace height="3em" depth="3em"/> <mo stretchy="true">)</mo>
+    </math>
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-fallback.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-fallback.html
new file mode 100644
index 00000000000..aab62087b59
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-fallback.html
@@ -0,0 +1,26 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>form fallback</title>
+    <link rel="help" href="https://mathml-refresh.github.io/mathml-core/#tokenmo">
+    <meta name="assert" content="Verify fallback to postfix/prefix forms.">
+    <link rel="match" href="mo-form-fallback-ref.html">
+  </head>
+  <body>
+
+    <!-- The left (respectively right) parenthesis only has a prefix
+         (respectively postfix) form which gives its stretchiness.
+         In theory, the parenthesis in the middle of the <math> element are
+         considered infix operators and should not stretch. Let's check that we
+         fallback to the postfix/prefix forms and actually make them stretchy.
+         This is to handle bad MathML markup that misses explicit <mrow> tags.
+      -->
+
+    <math>
+      <mo>(</mo> <mspace height="3em" depth="3em"/> <mo>)</mo>
+      <mo>(</mo> <mspace height="3em" depth="3em"/> <mo>)</mo>
+    </math>
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-minus-plus-ref.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-minus-plus-ref.html
new file mode 100644
index 00000000000..f8303337304
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-minus-plus-ref.html
@@ -0,0 +1,84 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>form plus/minus</title>
+  </head>
+  <body>
+
+    <!-- These operators should have form "prefix" -->
+
+    _<math><merror><mo form="prefix" lspace="0em" rspace="0.055555em">−</mo><mi>x</mi></merror></math>_
+    _<math><mo form="prefix" lspace="0em" rspace="0.055555em">−</mo><mi>x</mi></math>_
+    _<math><mphantom><mo form="prefix" lspace="0em" rspace="0.055555em">−</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo form="prefix" lspace="0em" rspace="0.055555em">−</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo form="prefix" lspace="0em" rspace="0.055555em">−</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo form="prefix" lspace="0em" rspace="0.055555em">−</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mo form="prefix" lspace="0em" rspace="0.055555em">+</mo><mi>x</mi></merror></math>_
+    _<math><mo form="prefix" lspace="0em" rspace="0.055555em">+</mo><mi>x</mi></math>_
+    _<math><mphantom><mo form="prefix" lspace="0em" rspace="0.055555em">+</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo form="prefix" lspace="0em" rspace="0.055555em">+</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo form="prefix" lspace="0em" rspace="0.055555em">+</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo form="prefix" lspace="0em" rspace="0.055555em">+</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mo form="prefix" lspace="0em" rspace="0.055555em">±</mo><mi>x</mi></merror></math>_
+    _<math><mo form="prefix" lspace="0em" rspace="0.055555em">±</mo><mi>x</mi></math>_
+    _<math><mphantom><mo form="prefix" lspace="0em" rspace="0.055555em">±</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo form="prefix" lspace="0em" rspace="0.055555em">±</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo form="prefix" lspace="0em" rspace="0.055555em">±</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo form="prefix" lspace="0em" rspace="0.055555em">±</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mo form="prefix" lspace="0em" rspace="0.055555em">∓</mo><mi>x</mi></merror></math>_
+    _<math><mo form="prefix" lspace="0em" rspace="0.055555em">∓</mo><mi>x</mi></math>_
+    _<math><mphantom><mo form="prefix" lspace="0em" rspace="0.055555em">∓</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo form="prefix" lspace="0em" rspace="0.055555em">∓</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo form="prefix" lspace="0em" rspace="0.055555em">∓</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo form="prefix" lspace="0em" rspace="0.055555em">∓</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    <!-- These operators should have form "infix" -->
+
+    _<math><merror><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">−</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">−</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">−</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">−</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">−</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">−</mo><mi>y</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">+</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">+</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">+</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">+</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">+</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">+</mo><mi>y</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">±</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">±</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">±</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">±</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">±</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">±</mo><mi>y</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">∓</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">∓</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">∓</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">∓</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">∓</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo form="infix" lspace="0.22222em" rspace="0.22222em">∓</mo><mi>y</mi></mstyle></math>_
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-minus-plus.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-minus-plus.html
new file mode 100644
index 00000000000..8a4ac3d7373
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-minus-plus.html
@@ -0,0 +1,87 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>form plus/minus</title>
+    <link rel="help" href="https://mathml-refresh.github.io/mathml-core/#tokenmo">
+    <meta name="assert" content="Verifies behavior of form of plus/minus etc.">
+    <link rel="match" href="mo-form-minus-plus-ref.html">
+  </head>
+  <body>
+
+    <!-- These operators should have form "prefix" -->
+
+    _<math><merror><mo>−</mo><mi>x</mi></merror></math>_
+    _<math><mo>−</mo><mi>x</mi></math>_
+    _<math><mphantom><mo>−</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo>−</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo>−</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo>−</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mo>+</mo><mi>x</mi></merror></math>_
+    _<math><mo>+</mo><mi>x</mi></math>_
+    _<math><mphantom><mo>+</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo>+</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo>+</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo>+</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mo>±</mo><mi>x</mi></merror></math>_
+    _<math><mo>±</mo><mi>x</mi></math>_
+    _<math><mphantom><mo>±</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo>±</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo>±</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo>±</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mo>∓</mo><mi>x</mi></merror></math>_
+    _<math><mo>∓</mo><mi>x</mi></math>_
+    _<math><mphantom><mo>∓</mo><mi>x</mi></mphantom></math>_
+    _<math><mrow><mo>∓</mo><mi>x</mi></mrow></math>_
+    _<math><msqrt><mo>∓</mo><mi>x</mi></msqrt></math>_
+    _<math><mstyle><mo>∓</mo><mi>x</mi></mstyle></math>_
+
+    <br/>
+
+    <!-- These operators should have form "infix" -->
+
+    _<math><merror><mi>x</mi><mo>−</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo>−</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo>−</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo>−</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo>−</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo>−</mo><mi>y</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mi>x</mi><mo>+</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo>+</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo>+</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo>+</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo>+</mo><mi>y</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mi>x</mi><mo>±</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo>±</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo>±</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo>±</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo>±</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo>±</mo><mi>y</mi></mstyle></math>_
+
+    <br/>
+
+    _<math><merror><mi>x</mi><mo>∓</mo><mi>y</mi></merror></math>_
+    _<math><mi>x</mi><mo>∓</mo><mi>y</mi></math>_
+    _<math><mphantom><mi>x</mi><mo>∓</mo><mi>y</mi></mphantom></math>_
+    _<math><mrow><mi>x</mi><mo>∓</mo><mi>y</mi></mrow></math>_
+    _<math><msqrt><mi>x</mi><mo>∓</mo><mi>y</mi></msqrt></math>_
+    _<math><mstyle><mi>x</mi><mo>∓</mo><mi>y</mi></mstyle></math>_
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-ref.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-ref.html
new file mode 100644
index 00000000000..d48bd48a6e4
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form-ref.html
@@ -0,0 +1,25 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>&lt;mo&gt; form attribute</title>
+  </head>
+  <body>
+
+    <!-- This checks the effect of @form on a prefix operator. -->
+    _<math><mo lspace="0.27777em" rspace="0.27777em">∇</mo></math>_
+    _<math><mo lspace="0.11111em" rspace="0.05555em">∇</mo></math>_
+    _<math><mo lspace="0.27777em" rspace="0.27777em">∇</mo></math>_
+
+    <!-- This checks the effect of @form on an infix operator. -->
+    _<math><mo lspace="0.22222em" rspace="0.22222em">⋉</mo></math>_
+    _<math><mo lspace="0.27777em" rspace="0.27777em">⋉</mo></math>_
+    _<math><mo lspace="0.27777em" rspace="0.27777em">⋉</mo></math>_
+
+    <!-- This checks the effect of @form on a postfix operator. -->
+    _<math><mo lspace="0.27777em" rspace="0.27777em">♭</mo></math>_
+    _<math><mo lspace="0.27777em" rspace="0.27777em">♭</mo></math>_
+    _<math><mo lspace="0em" rspace="0.11111em">♭</mo></math>_
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form.html b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form.html
new file mode 100644
index 00000000000..7c11c146911
--- /dev/null
+++ b/tests/wpt/web-platform-tests/mathml/presentation-markup/operators/mo-form.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8"/>
+    <title>&lt;mo&gt; form attribute</title>
+    <link rel="help" href="https://mathml-refresh.github.io/mathml-core/#tokenmo">
+    <meta name="assert" content="Verifies behavior of form attribute.">
+    <link rel="match" href="mo-form-ref.html">
+  </head>
+  <body>
+
+    <!-- This checks the effect of @form on a prefix operator. -->
+    _<math><mo form="infix">∇</mo></math>_
+    _<math><mo form="prefix">∇</mo></math>_
+    _<math><mo form="postfix">∇</mo></math>_
+
+    <!-- This checks the effect of @form on an infix operator. -->
+    _<math><mo form="infix">⋉</mo></math>_
+    _<math><mo form="prefix">⋉</mo></math>_
+    _<math><mo form="postfix">⋉</mo></math>_
+
+    <!-- This checks the effect of @form on a postfix operator. -->
+    _<math><mo form="infix">♭</mo></math>_
+    _<math><mo form="prefix">♭</mo></math>_
+    _<math><mo form="postfix">♭</mo></math>_
+
+  </body>
+</html>
diff --git a/tests/wpt/web-platform-tests/resources/test/tests/unit/META.yml b/tests/wpt/web-platform-tests/resources/test/tests/unit/META.yml
deleted file mode 100644
index cb9e3f87620..00000000000
--- a/tests/wpt/web-platform-tests/resources/test/tests/unit/META.yml
+++ /dev/null
@@ -1,2 +0,0 @@
-suggested_reviewers:
-  - tobie
diff --git a/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases-timeouts.html b/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases-timeouts.html
new file mode 100644
index 00000000000..760ac7154f1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases-timeouts.html
@@ -0,0 +1,120 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <meta name="timeout" content="long">
+  <script src="/resources/testharness.js"></script>
+  <title>Exceptional cases - timeouts</title>
+</head>
+<body>
+<p>
+  The tests in this file are executed in parallel to avoid exceeding the "long"
+  timeout duration.
+</p>
+<script>
+function makeTest(...bodies) {
+  const closeScript = '<' + '/script>';
+  let src = `
+<!DOCTYPE HTML>
+<html>
+<head>
+<title>Document title</title>
+<script src="/resources/testharness.js?${Math.random()}">${closeScript}
+</head>
+
+<body>
+<div id="log"></div>`;
+  bodies.forEach((body) => {
+    src += '<script>(' + body + ')();' + closeScript;
+  });
+
+  const iframe = document.createElement('iframe');
+
+  document.body.appendChild(iframe);
+  iframe.contentDocument.write(src);
+
+  return new Promise((resolve) => {
+    window.addEventListener('message', function onMessage(e) {
+      if (e.source !== iframe.contentWindow) {
+        return;
+      }
+      if (!e.data || e.data.type !=='complete') {
+        return;
+      }
+      window.removeEventListener('message', onMessage);
+      resolve(e.data);
+    });
+
+    iframe.contentDocument.close();
+  }).then(({ tests, status }) => {
+    const summary = {
+      harness: getEnumProp(status, status.status),
+      tests: {}
+    };
+
+    tests.forEach((test) => {
+      summary.tests[test.name] = getEnumProp(test, test.status);
+    });
+
+    return summary;
+  });
+}
+
+function getEnumProp(object, value) {
+  for (let property in object) {
+    if (!/^[A-Z]+$/.test(property)) {
+      continue;
+    }
+
+    if (object[property] === value) {
+      return property;
+    }
+  }
+}
+
+(() => {
+  window.asyncTestCleanupCount1 = 0;
+  const nestedTest = makeTest(
+    () => {
+      async_test((t) => {
+        t.add_cleanup(() => window.parent.asyncTestCleanupCount1 += 1);
+        setTimeout(() => {
+          throw new Error('this error is expected');
+        });
+      }, 'test');
+    }
+  );
+  promise_test(() => {
+    return nestedTest.then(({harness, tests}) => {
+        assert_equals(harness, 'ERROR');
+        assert_equals(tests.test, 'TIMEOUT');
+        assert_equals(window.asyncTestCleanupCount1, 1);
+      });
+  }, 'uncaught exception during async_test which times out');
+})();
+
+(() => {
+  window.promiseTestCleanupCount2 = 0;
+  const nestedTest = makeTest(
+    () => {
+      promise_test((t) => {
+        t.add_cleanup(() => window.parent.promiseTestCleanupCount2 += 1);
+        setTimeout(() => {
+          throw new Error('this error is expected');
+        });
+
+        return new Promise(() => {});
+      }, 'test');
+    }
+  );
+  promise_test(() => {
+    return nestedTest.then(({harness, tests}) => {
+        assert_equals(harness, 'ERROR');
+        assert_equals(tests.test, 'TIMEOUT');
+        assert_equals(window.promiseTestCleanupCount2, 1);
+      });
+  }, 'uncaught exception during promise_test which times out');
+})();
+</script>
+</body>
+</html>
diff --git a/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases.html b/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases.html
index 1a5335f6c1f..ef8f91bc61f 100644
--- a/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases.html
+++ b/tests/wpt/web-platform-tests/resources/test/tests/unit/exceptional-cases.html
@@ -115,44 +115,6 @@ promise_test(() => {
     });
 }, 'uncaught exception during promise_test');
 
-promise_test(() => {
-  window.asyncTestCleanupCount = 0;
-  return makeTest(
-      () => {
-        async_test((t) => {
-          t.add_cleanup(() => window.parent.asyncTestCleanupCount += 1);
-          setTimeout(() => {
-            throw new Error('this error is expected');
-          });
-        }, 'test');
-      }
-    ).then(({harness, tests}) => {
-      assert_equals(harness, 'ERROR');
-      assert_equals(tests.test, 'TIMEOUT');
-      assert_equals(window.asyncTestCleanupCount, 1);
-    });
-}, 'uncaught exception during async_test which times out');
-
-promise_test(() => {
-  window.promiseTestCleanupCount = 0;
-  return makeTest(
-      () => {
-        promise_test((t) => {
-          t.add_cleanup(() => window.parent.promiseTestCleanupCount += 1);
-          setTimeout(() => {
-            throw new Error('this error is expected');
-          });
-
-          return new Promise(() => {});
-        }, 'test');
-      }
-    ).then(({harness, tests}) => {
-      assert_equals(harness, 'ERROR');
-      assert_equals(tests.test, 'TIMEOUT');
-      assert_equals(window.promiseTestCleanupCount, 1);
-    });
-}, 'uncaught exception during promise_test which times out');
-
 promise_test(() => {
   return makeTest(
       () => { test(() => {}, 'before'); },
@@ -194,7 +156,6 @@ if ('onunhandledrejection' in window) {
   promise_test(() => {
     return makeTest(
         () => {
-          async_test('pending');
           async_test((t) => {
             Promise.reject(new Error('this error is expected'));
 
@@ -207,7 +168,6 @@ if ('onunhandledrejection' in window) {
         }
       ).then(({harness, tests}) => {
         assert_equals(harness, 'ERROR');
-        assert_equals(tests.pending, 'NOTRUN');
         assert_equals(tests.during, 'PASS');
         assert_equals(tests.after, 'PASS');
       });
@@ -249,8 +209,7 @@ if ('onunhandledrejection' in window) {
       ).then(({harness, tests}) => {
         assert_equals(harness, 'ERROR');
         assert_equals(tests.before, 'PASS');
-        // TODO: investigate why this is not present
-        assert_false('after' in tests);
+        assert_true('after' in tests);
       });
   }, 'unhandled rejection between tests');
 
@@ -286,8 +245,7 @@ if ('onunhandledrejection' in window) {
       ).then(({harness, tests}) => {
         assert_equals(harness, 'ERROR');
         assert_equals(tests.before, 'PASS');
-        // TODO: investigate why this is not present
-        assert_false('after' in tests);
+        assert_true('after' in tests);
       });
   }, 'unhandled rejection between promise_tests');
 
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/ready.https.html b/tests/wpt/web-platform-tests/service-workers/service-worker/ready.https.html
index ff5c793f2c2..6c1ed822a87 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/ready.https.html
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/ready.https.html
@@ -250,51 +250,68 @@ promise_test(function(t) {
   }, 'access ready after it has been resolved');
 
 promise_test(async function(t) {
-    var url = 'resources/empty-worker.js';
-    var matched_scope = 'resources/blank.html?ready-after-resurrect';
+  const url1 = 'resources/empty-worker.js';
+  const url2 = url1 + '?2';
+  const matched_scope = 'resources/blank.html?ready-after-unregister';
 
-    let reg1 = await service_worker_unregister_and_register(t, url, matched_scope);
-    add_completion_callback(function() {
-        reg1.unregister();
-      });
-    await wait_for_state(t, reg1.installing, 'activated');
+  const reg1 = await service_worker_unregister_and_register(t, url1, matched_scope);
+  t.add_cleanup(() => reg1.unregister());
 
-    // Hold the worker alive with a controlled worker
-    let frame = await with_iframe(matched_scope);
-    add_completion_callback(function() {
-        frame.remove();
-      });
+  await wait_for_state(t, reg1.installing, 'activating');
+  // This registration will resolve all ready promises in clients that match the scope.
+  // But there are no clients.
 
-    // Doom the registration as uninstalling.
-    await reg1.unregister();
+  const frame = await with_iframe(matched_scope);
+  t.add_cleanup(() => frame.remove());
 
-    // Access the ready promise while the registration is doomed.
-    let readyPromise = frame.contentWindow.navigator.serviceWorker.ready;
+  await reg1.unregister();
 
-    // Resurrect the doomed registration;
-    let reg2 = await service_worker_unregister_and_register(t, url, matched_scope);
-    assert_equals(reg1, reg2, 'existing registration should be resurrected');
+  // Access the ready promise while the registration is unregistering.
+  const readyPromise = frame.contentWindow.navigator.serviceWorker.ready;
 
-    // We are trying to test if the ready promise ever resolves here.  Use
-    // an explicit timeout check here rather than forcing a full infrastructure
-    // level timeout.
-    let timeoutId;
-    let timeoutPromise = new Promise(resolve => {
-      timeoutId = setTimeout(_ => {
-        timeoutId = null;
-        resolve();
-      }, 500);
-    });
+  // Create a new registration.
+  const reg2 = await navigator.serviceWorker.register(url2, { scope: matched_scope });
+  t.add_cleanup(() => reg2.unregister());
+  // This registration will resolve all ready promises in clients that match the scope.
+  // That includes frame's client.
 
-    // This should resolve immediately since there is an alive registration
-    // with an active promise for the matching scope.
-    await Promise.race([readyPromise, timeoutPromise]);
+  const readyReg = await readyPromise;
 
-    assert_not_equals(timeoutId, null,
-                      'ready promise should resolve before timeout');
-    clearTimeout(timeoutId);
+  assert_equals(readyReg.active.scriptURL, reg2.active.scriptURL, 'Resolves with the second registration');
+  assert_not_equals(reg1, reg2, 'Registrations should be different');
+}, 'resolve ready after unregistering and reregistering');
 
-    // We should get here and not time out.
+promise_test(async function(t) {
+  const url1 = 'resources/empty-worker.js';
+  const url2 = url1 + '?2';
+  const matched_scope = 'resources/blank.html?ready-after-unregister';
 
-  }, 'access ready on uninstalling registration that is resurrected');
+  const frame = await with_iframe(matched_scope);
+  t.add_cleanup(() => frame.remove());
+
+  const reg1 = await service_worker_unregister_and_register(t, url1, matched_scope);
+  t.add_cleanup(() => reg1.unregister());
+
+  await wait_for_state(t, reg1.installing, 'activated');
+  // This registration will resolve all ready promises in clients that match the scope.
+  // That includes frame's client.
+
+  const reg1Active = reg1.active;
+
+  await reg1.unregister();
+
+  // Access the ready promise while the registration is unregistering.
+  const readyPromise = frame.contentWindow.navigator.serviceWorker.ready;
+
+  // Create a new registration.
+  const reg2 = await navigator.serviceWorker.register(url2, { scope: matched_scope });
+  t.add_cleanup(() => reg2.unregister());
+  // This registration will resolve all ready promises in clients that match the scope.
+  // That includes frame's client, but its ready promise has already resolved.
+
+  const readyReg = await readyPromise;
+
+  assert_equals(readyReg.active.scriptURL, reg1Active.scriptURL, 'Resolves with the first registration');
+  assert_not_equals(reg1, reg2, 'Registrations should be different');
+}, 'resolve ready before unregistering and reregistering');
 </script>
diff --git a/tests/wpt/web-platform-tests/service-workers/service-worker/registration-end-to-end.https.html b/tests/wpt/web-platform-tests/service-workers/service-worker/registration-end-to-end.https.html
index e92b6502f09..1af4582d387 100644
--- a/tests/wpt/web-platform-tests/service-workers/service-worker/registration-end-to-end.https.html
+++ b/tests/wpt/web-platform-tests/service-workers/service-worker/registration-end-to-end.https.html
@@ -11,16 +11,11 @@ t.step(function() {
     var serviceWorkerStates = [];
     var lastServiceWorkerState = '';
     var receivedMessageFromPort = '';
-    var currentChangeCount = 0;
 
     assert_true(navigator.serviceWorker instanceof ServiceWorkerContainer);
     assert_equals(typeof navigator.serviceWorker.register, 'function');
     assert_equals(typeof navigator.serviceWorker.getRegistration, 'function');
 
-    navigator.serviceWorker.oncurrentchange = function() {
-        ++currentChangeCount;
-    };
-
     service_worker_unregister_and_register(
         t, 'resources/end-to-end-worker.js', scope)
       .then(onRegister)
@@ -75,9 +70,6 @@ t.step(function() {
                                 ['installing', 'installed', 'activating', 'activated'],
                                 'Service worker should pass through all states');
 
-            assert_equals(currentChangeCount, 0,
-                          'Should not see current changes since document is out of scope');
-
             assert_equals(receivedMessageFromPort, 'Ack for: registering doc');
 
             var sawRedundant = new Promise(t.step_func(function(resolve) {
diff --git a/tests/wpt/web-platform-tests/svg/extensibility/foreignObject/foreign-object-under-defs-crash.html b/tests/wpt/web-platform-tests/svg/extensibility/foreignObject/foreign-object-under-defs-crash.html
new file mode 100644
index 00000000000..08c47454b6c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/svg/extensibility/foreignObject/foreign-object-under-defs-crash.html
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<title>Should not crash on foreignObject under defs</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script>test(()=>{})</script>
+<div style="will-change: opacity; mix-blend-mode: exclusion;"></div>
+<svg>
+  <defs>
+    <foreignObject width="100" height="100">
+      <div style="will-change: opacity;">FAIL</div>
+    </foreignObject>
+  </defs>
+</svg>
+<div style="will-change: opacity;"></div>
diff --git a/tests/wpt/web-platform-tests/tools/ci/azure/cleanup_win10.yml b/tests/wpt/web-platform-tests/tools/ci/azure/cleanup_win10.yml
index ba08b7eafab..4abb35369de 100644
--- a/tests/wpt/web-platform-tests/tools/ci/azure/cleanup_win10.yml
+++ b/tests/wpt/web-platform-tests/tools/ci/azure/cleanup_win10.yml
@@ -3,10 +3,35 @@
 # necessary because the Windows 10 agents aren't reset between each job.
 steps:
 - powershell: |
+    function UninstallEdge($edgePath, $uninstallArgs) {
+      try {
+        cmd /c taskkill /f /im msedge* `> nul 2`> nul
+        cmd /c taskkill /f /im setup.exe `> nul 2`> nul
+        if (Test-Path $edgePath) {
+          $installerPath = Get-ChildItem -PATH $edgePath -Filter "setup.exe" -Recurse | Select -First 1 FullName
+          if (Test-Path $installerPath.FullName) {
+            Write-Host "Uninstall: $($installerPath.FullName) $uninstallArgs"
+            Start-Process "$($installerPath.FullName)" -ArgumentList $uninstallArgs -Wait
+            Remove-Item -Path $edgePath -Recurse -Force -ErrorAction SilentlyContinue
+          }
+        }
+      } catch [Exception] {
+        Write-Host "Failed to unstall Edge from $edgePath. ERROR= $($_.Exception.Message)" -ForegroundColor Red
+      }
+    }
+
+    # restore hosts file
     $hostFile = "$env:systemroot\System32\drivers\etc\hosts"
     Copy-Item -Path "$hostFile.back" -Destination $hostFile -Force
-    taskkill /f /im MicrosoftEdge*
-    taskkill /f /im MicrosoftWebDriver.exe
+
+    # uninstall Edge
+    UninstallEdge "$env:localappdata\Microsoft\Edge\Application" "--uninstall --force-uninstall"
+    # uninstall Edge Canary channel
+    UninstallEdge "$env:localappdata\Microsoft\Edge SxS\Application" "--uninstall --msedge-sxs --system-level --force-uninstall"
+    # uninstall Edge Dev channel
+    UninstallEdge "$env:systemdrive\Program Files (x86)\Microsoft\Edge Dev\Application" "--uninstall --msedge-dev --system-level --force-uninstall"
+    # uninstall Edge Beta channel
+    UninstallEdge "$env:systemdrive\Program Files (x86)\Microsoft\Edge Beta\Application" "--uninstall --msedge-beta --system-level --force-uninstall"
   displayName: 'Restore hosts file and cleanup test machine'
   condition: always()
   errorActionPreference: silentlyContinue
diff --git a/tests/wpt/web-platform-tests/tools/ci/azure/install_edge.yml b/tests/wpt/web-platform-tests/tools/ci/azure/install_edge.yml
new file mode 100644
index 00000000000..a70dc78e01c
--- /dev/null
+++ b/tests/wpt/web-platform-tests/tools/ci/azure/install_edge.yml
@@ -0,0 +1,32 @@
+parameters:
+  channel: dev
+
+# Should match https://web-platform-tests.org/running-tests/chrome.html
+# Just replace chrome with edgechromium
+steps:
+- ${{ if eq(parameters.channel, 'canary') }}:
+  - powershell: |
+      $edgeInstallerName = 'MicrosoftEdgeSetup.exe'
+      # Link to Canary channel installer
+      Start-BitsTransfer -Source 'https://go.microsoft.com/fwlink/?linkid=2084649&Channel=Canary&language=en-us' -Destination MicrosoftEdgeSetup.exe
+      cmd /c START /WAIT $edgeInstallerName /silent /install
+      $edgePath = "$env:localappdata\Microsoft\Edge SxS\Application"
+      if (Test-Path $edgePath) {
+        Write-Host "##vso[task.prependpath]$edgePath"
+      } else {
+        Throw "Failed to install Edge at $edgePath"
+      }
+    displayName: 'Install Edge Canary'
+- ${{ if eq(parameters.channel, 'dev') }}:
+  - powershell: |
+      $edgeInstallerName = 'MicrosoftEdgeSetup.exe'
+      # Link to Dev channel installer
+      Start-BitsTransfer -Source 'https://go.microsoft.com/fwlink/?linkid=2069324&Channel=Dev&language=en-us' -Destination MicrosoftEdgeSetup.exe
+      cmd /c START /WAIT $edgeInstallerName /silent /install
+      $edgePath = "$env:systemdrive\Program Files (x86)\Microsoft\Edge Dev\Application"
+      if (Test-Path $edgePath) {
+        Write-Host "##vso[task.prependpath]$edgePath"
+      } else {
+        Throw "Failed to install Edge at $edgePath"
+      }
+    displayName: 'Install Edge Dev'
diff --git a/tests/wpt/web-platform-tests/tools/ci/azure/install_safari.yml b/tests/wpt/web-platform-tests/tools/ci/azure/install_safari.yml
index be18f837646..bfb6afc332b 100644
--- a/tests/wpt/web-platform-tests/tools/ci/azure/install_safari.yml
+++ b/tests/wpt/web-platform-tests/tools/ci/azure/install_safari.yml
@@ -7,7 +7,10 @@ steps:
   - script: |
       # This is equivalent to `Homebrew/homebrew-cask-versions/safari-technology-preview`,
       # but the raw URL is used to bypass caching.
-      HOMEBREW_NO_AUTO_UPDATE=1 brew cask install https://raw.githubusercontent.com/Homebrew/homebrew-cask-versions/master/Casks/safari-technology-preview.rb
+      # Safari Technology Preview version 83 includes a regression that
+      # interferes with results collection. The version of the installation
+      # script referenced here installs STP at version 82.
+      HOMEBREW_NO_AUTO_UPDATE=1 brew cask install https://raw.githubusercontent.com/Homebrew/homebrew-cask-versions/dbde508bb83254c53be4eb6387dbd9fbf9797a35/Casks/safari-technology-preview.rb
       sudo "/Applications/Safari Technology Preview.app/Contents/MacOS/safaridriver" --enable
       defaults write com.apple.SafariTechnologyPreview WebKitJavaScriptCanOpenWindowsAutomatically 1
       defaults write com.apple.SafariTechnologyPreview ExperimentalServerTimingEnabled 1
diff --git a/tests/wpt/web-platform-tests/tools/wpt/browser.py b/tests/wpt/web-platform-tests/tools/wpt/browser.py
index e2c9341bd67..b093600b596 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/browser.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/browser.py
@@ -697,7 +697,7 @@ class EdgeChromium(Browser):
         return find_executable("msedgedriver")
 
     def install_webdriver(self, dest=None, channel=None, browser_binary=None):
-        if self.platform == "win":
+        if self.platform != "win":
             raise ValueError("Only Windows platform is currently supported")
 
         if dest is None:
diff --git a/tests/wpt/web-platform-tests/tools/wpt/run.py b/tests/wpt/web-platform-tests/tools/wpt/run.py
index 07376797f58..0d7fa2233d6 100644
--- a/tests/wpt/web-platform-tests/tools/wpt/run.py
+++ b/tests/wpt/web-platform-tests/tools/wpt/run.py
@@ -354,6 +354,9 @@ class EdgeChromium(BrowserSetup):
                 kwargs["webdriver_binary"] = webdriver_binary
             else:
                 raise WptrunError("Unable to locate or install msedgedriver binary")
+        if kwargs["browser_channel"] == "dev":
+            logger.info("Automatically turning on experimental features for Edge Dev")
+            kwargs["binary_args"].append("--enable-experimental-web-platform-features")
 
 
 class Edge(BrowserSetup):