diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 971c478c1b2a..12dc2af872eb 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -1708,6 +1708,29 @@ impl Element {
         self.set_attribute(local_name, AttrValue::String(value.into()));
     }
 
+    /// Used for string attribute reflections where absence of the attribute returns `null`,
+    /// e.g. `element.ariaLabel` returning `null` when the `aria-label` attribute is absent.
+    fn get_nullable_string_attribute(&self, local_name: &LocalName) -> Option<DOMString> {
+        if self.has_attribute(local_name) {
+            Some(self.get_string_attribute(local_name))
+        } else {
+            None
+        }
+    }
+
+    /// Used for string attribute reflections where setting `null`/`undefined` removes the
+    /// attribute, e.g. `element.ariaLabel = null` removing the `aria-label` attribute.
+    fn set_nullable_string_attribute(&self, local_name: &LocalName, value: Option<DOMString>) {
+        match value {
+            Some(val) => {
+                self.set_string_attribute(local_name, val);
+            },
+            None => {
+                self.remove_attribute(&ns!(), local_name);
+            },
+        }
+    }
+
     pub fn get_tokenlist_attribute(&self, local_name: &LocalName) -> Vec<Atom> {
         self.get_attribute(&ns!(), local_name)
             .map(|attr| attr.value().as_tokens().to_vec())
@@ -2907,6 +2930,358 @@ impl ElementMethods for Element {
     fn AttachShadow(&self) -> Fallible<DomRoot<ShadowRoot>> {
         self.attach_shadow(IsUserAgentWidget::No)
     }
+
+    fn GetRole(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("role"))
+    }
+
+    fn SetRole(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("role"), value);
+    }
+
+    fn GetAriaAtomic(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-atomic"))
+    }
+
+    fn SetAriaAtomic(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-atomic"), value);
+    }
+
+    fn GetAriaAutoComplete(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-autocomplete"))
+    }
+
+    fn SetAriaAutoComplete(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-autocomplete"), value);
+    }
+
+    fn GetAriaBrailleLabel(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-braillelabel"))
+    }
+
+    fn SetAriaBrailleLabel(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-braillelabel"), value);
+    }
+
+    fn GetAriaBrailleRoleDescription(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-brailleroledescription"))
+    }
+
+    fn SetAriaBrailleRoleDescription(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-brailleroledescription"), value);
+    }
+
+    fn GetAriaBusy(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-busy"))
+    }
+
+    fn SetAriaBusy(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-busy"), value);
+    }
+
+    fn GetAriaChecked(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-checked"))
+    }
+
+    fn SetAriaChecked(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-checked"), value);
+    }
+
+    fn GetAriaColCount(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-colcount"))
+    }
+
+    fn SetAriaColCount(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-colcount"), value);
+    }
+
+    fn GetAriaColIndex(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-colindex"))
+    }
+
+    fn SetAriaColIndex(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-colindex"), value);
+    }
+
+    fn GetAriaColIndexText(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-colindextext"))
+    }
+
+    fn SetAriaColIndexText(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-colindextext"), value);
+    }
+
+    fn GetAriaColSpan(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-colspan"))
+    }
+
+    fn SetAriaColSpan(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-colspan"), value);
+    }
+
+    fn GetAriaCurrent(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-current"))
+    }
+
+    fn SetAriaCurrent(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-current"), value);
+    }
+
+    fn GetAriaDescription(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-description"))
+    }
+
+    fn SetAriaDescription(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-description"), value);
+    }
+
+    fn GetAriaDisabled(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-disabled"))
+    }
+
+    fn SetAriaDisabled(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-disabled"), value);
+    }
+
+    fn GetAriaExpanded(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-expanded"))
+    }
+
+    fn SetAriaExpanded(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-expanded"), value);
+    }
+
+    fn GetAriaHasPopup(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-haspopup"))
+    }
+
+    fn SetAriaHasPopup(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-haspopup"), value);
+    }
+
+    fn GetAriaHidden(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-hidden"))
+    }
+
+    fn SetAriaHidden(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-hidden"), value);
+    }
+
+    fn GetAriaInvalid(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-invalid"))
+    }
+
+    fn SetAriaInvalid(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-invalid"), value);
+    }
+
+    fn GetAriaKeyShortcuts(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-keyshortcuts"))
+    }
+
+    fn SetAriaKeyShortcuts(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-keyshortcuts"), value);
+    }
+
+    fn GetAriaLabel(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-label"))
+    }
+
+    fn SetAriaLabel(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-label"), value);
+    }
+
+    fn GetAriaLevel(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-level"))
+    }
+
+    fn SetAriaLevel(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-level"), value);
+    }
+
+    fn GetAriaLive(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-live"))
+    }
+
+    fn SetAriaLive(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-live"), value);
+    }
+
+    fn GetAriaModal(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-modal"))
+    }
+
+    fn SetAriaModal(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-modal"), value);
+    }
+
+    fn GetAriaMultiLine(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-multiline"))
+    }
+
+    fn SetAriaMultiLine(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-multiline"), value);
+    }
+
+    fn GetAriaMultiSelectable(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-multiselectable"))
+    }
+
+    fn SetAriaMultiSelectable(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-multiselectable"), value);
+    }
+
+    fn GetAriaOrientation(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-orientation"))
+    }
+
+    fn SetAriaOrientation(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-orientation"), value);
+    }
+
+    fn GetAriaPlaceholder(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-placeholder"))
+    }
+
+    fn SetAriaPlaceholder(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-placeholder"), value);
+    }
+
+    fn GetAriaPosInSet(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-posinset"))
+    }
+
+    fn SetAriaPosInSet(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-posinset"), value);
+    }
+
+    fn GetAriaPressed(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-pressed"))
+    }
+
+    fn SetAriaPressed(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-pressed"), value);
+    }
+
+    fn GetAriaReadOnly(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-readonly"))
+    }
+
+    fn SetAriaReadOnly(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-readonly"), value);
+    }
+
+    fn GetAriaRelevant(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-relevant"))
+    }
+
+    fn SetAriaRelevant(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-relevant"), value);
+    }
+
+    fn GetAriaRequired(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-required"))
+    }
+
+    fn SetAriaRequired(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-required"), value);
+    }
+
+    fn GetAriaRoleDescription(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-roledescription"))
+    }
+
+    fn SetAriaRoleDescription(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-roledescription"), value);
+    }
+
+    fn GetAriaRowCount(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-rowcount"))
+    }
+
+    fn SetAriaRowCount(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-rowcount"), value);
+    }
+
+    fn GetAriaRowIndex(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-rowindex"))
+    }
+
+    fn SetAriaRowIndex(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-rowindex"), value);
+    }
+
+    fn GetAriaRowIndexText(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-rowindextext"))
+    }
+
+    fn SetAriaRowIndexText(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-rowindextext"), value);
+    }
+
+    fn GetAriaRowSpan(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-rowspan"))
+    }
+
+    fn SetAriaRowSpan(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-rowspan"), value);
+    }
+
+    fn GetAriaSelected(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-selected"))
+    }
+
+    fn SetAriaSelected(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-selected"), value);
+    }
+
+    fn GetAriaSetSize(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-setsize"))
+    }
+
+    fn SetAriaSetSize(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-setsize"), value);
+    }
+
+    fn GetAriaSort(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-sort"))
+    }
+
+    fn SetAriaSort(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-sort"), value);
+    }
+
+    fn GetAriaValueMax(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-valuemax"))
+    }
+
+    fn SetAriaValueMax(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-valuemax"), value);
+    }
+
+    fn GetAriaValueMin(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-valuemin"))
+    }
+
+    fn SetAriaValueMin(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-valuemin"), value);
+    }
+
+    fn GetAriaValueNow(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-valuenow"))
+    }
+
+    fn SetAriaValueNow(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-valuenow"), value);
+    }
+
+    fn GetAriaValueText(&self) -> Option<DOMString> {
+        self.get_nullable_string_attribute(&local_name!("aria-valuetext"))
+    }
+
+    fn SetAriaValueText(&self, value: Option<DOMString>) {
+        self.set_nullable_string_attribute(&local_name!("aria-valuetext"), value);
+    }
 }
 
 impl VirtualMethods for Element {
diff --git a/components/script/dom/webidls/ARIAMixin.webidl b/components/script/dom/webidls/ARIAMixin.webidl
new file mode 100644
index 000000000000..3377b09e619c
--- /dev/null
+++ b/components/script/dom/webidls/ARIAMixin.webidl
@@ -0,0 +1,57 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+/*
+ * The origin of this IDL file is
+ * https://w3c.github.io/aria/#dom-ariamixin
+ *
+ * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
+ * liability, trademark and document use rules apply.
+ */
+
+interface mixin ARIAMixin {
+  [CEReactions] attribute DOMString? role;
+  [CEReactions] attribute DOMString? ariaAtomic;
+  [CEReactions] attribute DOMString? ariaAutoComplete;
+  [CEReactions] attribute DOMString? ariaBrailleLabel;
+  [CEReactions] attribute DOMString? ariaBrailleRoleDescription;
+  [CEReactions] attribute DOMString? ariaBusy;
+  [CEReactions] attribute DOMString? ariaChecked;
+  [CEReactions] attribute DOMString? ariaColCount;
+  [CEReactions] attribute DOMString? ariaColIndex;
+  [CEReactions] attribute DOMString? ariaColIndexText;
+  [CEReactions] attribute DOMString? ariaColSpan;
+  [CEReactions] attribute DOMString? ariaCurrent;
+  [CEReactions] attribute DOMString? ariaDescription;
+  [CEReactions] attribute DOMString? ariaDisabled;
+  [CEReactions] attribute DOMString? ariaExpanded;
+  [CEReactions] attribute DOMString? ariaHasPopup;
+  [CEReactions] attribute DOMString? ariaHidden;
+  [CEReactions] attribute DOMString? ariaInvalid;
+  [CEReactions] attribute DOMString? ariaKeyShortcuts;
+  [CEReactions] attribute DOMString? ariaLabel;
+  [CEReactions] attribute DOMString? ariaLevel;
+  [CEReactions] attribute DOMString? ariaLive;
+  [CEReactions] attribute DOMString? ariaModal;
+  [CEReactions] attribute DOMString? ariaMultiLine;
+  [CEReactions] attribute DOMString? ariaMultiSelectable;
+  [CEReactions] attribute DOMString? ariaOrientation;
+  [CEReactions] attribute DOMString? ariaPlaceholder;
+  [CEReactions] attribute DOMString? ariaPosInSet;
+  [CEReactions] attribute DOMString? ariaPressed;
+  [CEReactions] attribute DOMString? ariaReadOnly;
+  [CEReactions] attribute DOMString? ariaRelevant;
+  [CEReactions] attribute DOMString? ariaRequired;
+  [CEReactions] attribute DOMString? ariaRoleDescription;
+  [CEReactions] attribute DOMString? ariaRowCount;
+  [CEReactions] attribute DOMString? ariaRowIndex;
+  [CEReactions] attribute DOMString? ariaRowIndexText;
+  [CEReactions] attribute DOMString? ariaRowSpan;
+  [CEReactions] attribute DOMString? ariaSelected;
+  [CEReactions] attribute DOMString? ariaSetSize;
+  [CEReactions] attribute DOMString? ariaSort;
+  [CEReactions] attribute DOMString? ariaValueMax;
+  [CEReactions] attribute DOMString? ariaValueMin;
+  [CEReactions] attribute DOMString? ariaValueNow;
+  [CEReactions] attribute DOMString? ariaValueText;
+};
diff --git a/components/script/dom/webidls/Element.webidl b/components/script/dom/webidls/Element.webidl
index 9c3980e527fb..e5c503ef3836 100644
--- a/components/script/dom/webidls/Element.webidl
+++ b/components/script/dom/webidls/Element.webidl
@@ -127,3 +127,4 @@ Element includes ChildNode;
 Element includes NonDocumentTypeChildNode;
 Element includes ParentNode;
 Element includes ActivatableElement;
+Element includes ARIAMixin;
diff --git a/tests/wpt/meta-legacy-layout/custom-elements/reactions/AriaMixin-string-attributes.html.ini b/tests/wpt/meta-legacy-layout/custom-elements/reactions/AriaMixin-string-attributes.html.ini
deleted file mode 100644
index 388edda3974f..000000000000
--- a/tests/wpt/meta-legacy-layout/custom-elements/reactions/AriaMixin-string-attributes.html.ini
+++ /dev/null
@@ -1,228 +0,0 @@
-[AriaMixin-string-attributes.html]
-  [ariaAtomic on Element must enqueue an attributeChanged reaction when adding aria-atomic content attribute]
-    expected: FAIL
-
-  [ariaAtomic on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaAutoComplete on Element must enqueue an attributeChanged reaction when adding aria-autocomplete content attribute]
-    expected: FAIL
-
-  [ariaAutoComplete on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaBusy on Element must enqueue an attributeChanged reaction when adding aria-busy content attribute]
-    expected: FAIL
-
-  [ariaBusy on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaChecked on Element must enqueue an attributeChanged reaction when adding aria-checked content attribute]
-    expected: FAIL
-
-  [ariaChecked on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaColCount on Element must enqueue an attributeChanged reaction when adding aria-colcount content attribute]
-    expected: FAIL
-
-  [ariaColCount on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaColIndex on Element must enqueue an attributeChanged reaction when adding aria-colindex content attribute]
-    expected: FAIL
-
-  [ariaColIndex on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaColSpan on Element must enqueue an attributeChanged reaction when adding aria-colspan content attribute]
-    expected: FAIL
-
-  [ariaColSpan on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaCurrent on Element must enqueue an attributeChanged reaction when adding aria-current content attribute]
-    expected: FAIL
-
-  [ariaCurrent on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaDisabled on Element must enqueue an attributeChanged reaction when adding aria-disabled content attribute]
-    expected: FAIL
-
-  [ariaDisabled on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaExpanded on Element must enqueue an attributeChanged reaction when adding aria-expanded content attribute]
-    expected: FAIL
-
-  [ariaExpanded on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaHasPopup on Element must enqueue an attributeChanged reaction when adding aria-haspopup content attribute]
-    expected: FAIL
-
-  [ariaHasPopup on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaHidden on Element must enqueue an attributeChanged reaction when adding aria-hidden content attribute]
-    expected: FAIL
-
-  [ariaHidden on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaInvalid on Element must enqueue an attributeChanged reaction when adding aria-invalid content attribute]
-    expected: FAIL
-
-  [ariaInvalid on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaKeyShortcuts on Element must enqueue an attributeChanged reaction when adding aria-keyshortcuts content attribute]
-    expected: FAIL
-
-  [ariaKeyShortcuts on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaLabel on Element must enqueue an attributeChanged reaction when adding aria-label content attribute]
-    expected: FAIL
-
-  [ariaLabel on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaLevel on Element must enqueue an attributeChanged reaction when adding aria-level content attribute]
-    expected: FAIL
-
-  [ariaLevel on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaLive on Element must enqueue an attributeChanged reaction when adding aria-live content attribute]
-    expected: FAIL
-
-  [ariaLive on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaModal on Element must enqueue an attributeChanged reaction when adding aria-modal content attribute]
-    expected: FAIL
-
-  [ariaModal on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaMultiLine on Element must enqueue an attributeChanged reaction when adding aria-multiline content attribute]
-    expected: FAIL
-
-  [ariaMultiLine on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaMultiSelectable on Element must enqueue an attributeChanged reaction when adding aria-multiselectable content attribute]
-    expected: FAIL
-
-  [ariaMultiSelectable on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaOrientation on Element must enqueue an attributeChanged reaction when adding aria-orientation content attribute]
-    expected: FAIL
-
-  [ariaOrientation on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaPlaceholder on Element must enqueue an attributeChanged reaction when adding aria-placeholder content attribute]
-    expected: FAIL
-
-  [ariaPlaceholder on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaPosInSet on Element must enqueue an attributeChanged reaction when adding aria-posinset content attribute]
-    expected: FAIL
-
-  [ariaPosInSet on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaPressed on Element must enqueue an attributeChanged reaction when adding aria-pressed content attribute]
-    expected: FAIL
-
-  [ariaPressed on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaReadOnly on Element must enqueue an attributeChanged reaction when adding aria-readonly content attribute]
-    expected: FAIL
-
-  [ariaReadOnly on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRelevant on Element must enqueue an attributeChanged reaction when adding aria-relevant content attribute]
-    expected: FAIL
-
-  [ariaRelevant on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRequired on Element must enqueue an attributeChanged reaction when adding aria-required content attribute]
-    expected: FAIL
-
-  [ariaRequired on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRoleDescription on Element must enqueue an attributeChanged reaction when adding aria-roledescription content attribute]
-    expected: FAIL
-
-  [ariaRoleDescription on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRowCount on Element must enqueue an attributeChanged reaction when adding aria-rowcount content attribute]
-    expected: FAIL
-
-  [ariaRowCount on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRowIndex on Element must enqueue an attributeChanged reaction when adding aria-rowindex content attribute]
-    expected: FAIL
-
-  [ariaRowIndex on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRowSpan on Element must enqueue an attributeChanged reaction when adding aria-rowspan content attribute]
-    expected: FAIL
-
-  [ariaRowSpan on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaSelected on Element must enqueue an attributeChanged reaction when adding aria-selected content attribute]
-    expected: FAIL
-
-  [ariaSelected on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaSetSize on Element must enqueue an attributeChanged reaction when adding aria-setsize content attribute]
-    expected: FAIL
-
-  [ariaSetSize on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaSort on Element must enqueue an attributeChanged reaction when adding aria-sort content attribute]
-    expected: FAIL
-
-  [ariaSort on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueMax on Element must enqueue an attributeChanged reaction when adding aria-valuemax content attribute]
-    expected: FAIL
-
-  [ariaValueMax on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueMin on Element must enqueue an attributeChanged reaction when adding aria-valuemin content attribute]
-    expected: FAIL
-
-  [ariaValueMin on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueNow on Element must enqueue an attributeChanged reaction when adding aria-valuenow content attribute]
-    expected: FAIL
-
-  [ariaValueNow on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueText on Element must enqueue an attributeChanged reaction when adding aria-valuetext content attribute]
-    expected: FAIL
-
-  [ariaValueText on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
diff --git a/tests/wpt/meta-legacy-layout/html/dom/aria-attribute-reflection.html.ini b/tests/wpt/meta-legacy-layout/html/dom/aria-attribute-reflection.html.ini
deleted file mode 100644
index ba427c34c985..000000000000
--- a/tests/wpt/meta-legacy-layout/html/dom/aria-attribute-reflection.html.ini
+++ /dev/null
@@ -1,126 +0,0 @@
-[aria-attribute-reflection.html]
-  [role attribute reflects.]
-    expected: FAIL
-
-  [aria-atomic attribute reflects.]
-    expected: FAIL
-
-  [aria-autocomplete attribute reflects.]
-    expected: FAIL
-
-  [aria-busy attribute reflects.]
-    expected: FAIL
-
-  [aria-checked attribute reflects.]
-    expected: FAIL
-
-  [aria-colcount attribute reflects.]
-    expected: FAIL
-
-  [aria-colindex attribute reflects.]
-    expected: FAIL
-
-  [aria-colspan attribute reflects.]
-    expected: FAIL
-
-  [aria-current attribute reflects.]
-    expected: FAIL
-
-  [aria-description attribute reflects.]
-    expected: FAIL
-
-  [aria-disabled attribute reflects.]
-    expected: FAIL
-
-  [aria-expanded attribute reflects.]
-    expected: FAIL
-
-  [aria-haspopup attribute reflects.]
-    expected: FAIL
-
-  [aria-hidden attribute reflects.]
-    expected: FAIL
-
-  [aria-invalid attribute reflects.]
-    expected: FAIL
-
-  [aria-keyshortcuts attribute reflects.]
-    expected: FAIL
-
-  [aria-label attribute reflects.]
-    expected: FAIL
-
-  [aria-level attribute reflects.]
-    expected: FAIL
-
-  [aria-live attribute reflects.]
-    expected: FAIL
-
-  [aria-modal attribute reflects.]
-    expected: FAIL
-
-  [aria-multiline attribute reflects.]
-    expected: FAIL
-
-  [aria-multiselectable attribute reflects.]
-    expected: FAIL
-
-  [aria-orientation attribute reflects.]
-    expected: FAIL
-
-  [aria-placeholder attribute reflects.]
-    expected: FAIL
-
-  [aria-posinset attribute reflects.]
-    expected: FAIL
-
-  [aria-pressed attribute reflects.]
-    expected: FAIL
-
-  [aria-readonly attribute reflects.]
-    expected: FAIL
-
-  [aria-relevant attribute reflects.]
-    expected: FAIL
-
-  [aria-required attribute reflects.]
-    expected: FAIL
-
-  [aria-roledescription attribute reflects.]
-    expected: FAIL
-
-  [aria-rowcount attribute reflects.]
-    expected: FAIL
-
-  [aria-rowindex attribute reflects.]
-    expected: FAIL
-
-  [aria-rowspan attribute reflects.]
-    expected: FAIL
-
-  [aria-selected attribute reflects.]
-    expected: FAIL
-
-  [aria-setsize attribute reflects.]
-    expected: FAIL
-
-  [aria-sort attribute reflects.]
-    expected: FAIL
-
-  [aria-valuemax attribute reflects.]
-    expected: FAIL
-
-  [aria-valuemin attribute reflects.]
-    expected: FAIL
-
-  [aria-valuenow attribute reflects.]
-    expected: FAIL
-
-  [aria-valuetext attribute reflects.]
-    expected: FAIL
-
-  [aria-braillelabel attribute reflects.]
-    expected: FAIL
-
-  [aria-brailleroledescription attribute reflects.]
-    expected: FAIL
diff --git a/tests/wpt/meta/custom-elements/reactions/AriaMixin-string-attributes.html.ini b/tests/wpt/meta/custom-elements/reactions/AriaMixin-string-attributes.html.ini
deleted file mode 100644
index 388edda3974f..000000000000
--- a/tests/wpt/meta/custom-elements/reactions/AriaMixin-string-attributes.html.ini
+++ /dev/null
@@ -1,228 +0,0 @@
-[AriaMixin-string-attributes.html]
-  [ariaAtomic on Element must enqueue an attributeChanged reaction when adding aria-atomic content attribute]
-    expected: FAIL
-
-  [ariaAtomic on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaAutoComplete on Element must enqueue an attributeChanged reaction when adding aria-autocomplete content attribute]
-    expected: FAIL
-
-  [ariaAutoComplete on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaBusy on Element must enqueue an attributeChanged reaction when adding aria-busy content attribute]
-    expected: FAIL
-
-  [ariaBusy on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaChecked on Element must enqueue an attributeChanged reaction when adding aria-checked content attribute]
-    expected: FAIL
-
-  [ariaChecked on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaColCount on Element must enqueue an attributeChanged reaction when adding aria-colcount content attribute]
-    expected: FAIL
-
-  [ariaColCount on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaColIndex on Element must enqueue an attributeChanged reaction when adding aria-colindex content attribute]
-    expected: FAIL
-
-  [ariaColIndex on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaColSpan on Element must enqueue an attributeChanged reaction when adding aria-colspan content attribute]
-    expected: FAIL
-
-  [ariaColSpan on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaCurrent on Element must enqueue an attributeChanged reaction when adding aria-current content attribute]
-    expected: FAIL
-
-  [ariaCurrent on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaDisabled on Element must enqueue an attributeChanged reaction when adding aria-disabled content attribute]
-    expected: FAIL
-
-  [ariaDisabled on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaExpanded on Element must enqueue an attributeChanged reaction when adding aria-expanded content attribute]
-    expected: FAIL
-
-  [ariaExpanded on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaHasPopup on Element must enqueue an attributeChanged reaction when adding aria-haspopup content attribute]
-    expected: FAIL
-
-  [ariaHasPopup on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaHidden on Element must enqueue an attributeChanged reaction when adding aria-hidden content attribute]
-    expected: FAIL
-
-  [ariaHidden on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaInvalid on Element must enqueue an attributeChanged reaction when adding aria-invalid content attribute]
-    expected: FAIL
-
-  [ariaInvalid on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaKeyShortcuts on Element must enqueue an attributeChanged reaction when adding aria-keyshortcuts content attribute]
-    expected: FAIL
-
-  [ariaKeyShortcuts on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaLabel on Element must enqueue an attributeChanged reaction when adding aria-label content attribute]
-    expected: FAIL
-
-  [ariaLabel on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaLevel on Element must enqueue an attributeChanged reaction when adding aria-level content attribute]
-    expected: FAIL
-
-  [ariaLevel on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaLive on Element must enqueue an attributeChanged reaction when adding aria-live content attribute]
-    expected: FAIL
-
-  [ariaLive on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaModal on Element must enqueue an attributeChanged reaction when adding aria-modal content attribute]
-    expected: FAIL
-
-  [ariaModal on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaMultiLine on Element must enqueue an attributeChanged reaction when adding aria-multiline content attribute]
-    expected: FAIL
-
-  [ariaMultiLine on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaMultiSelectable on Element must enqueue an attributeChanged reaction when adding aria-multiselectable content attribute]
-    expected: FAIL
-
-  [ariaMultiSelectable on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaOrientation on Element must enqueue an attributeChanged reaction when adding aria-orientation content attribute]
-    expected: FAIL
-
-  [ariaOrientation on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaPlaceholder on Element must enqueue an attributeChanged reaction when adding aria-placeholder content attribute]
-    expected: FAIL
-
-  [ariaPlaceholder on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaPosInSet on Element must enqueue an attributeChanged reaction when adding aria-posinset content attribute]
-    expected: FAIL
-
-  [ariaPosInSet on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaPressed on Element must enqueue an attributeChanged reaction when adding aria-pressed content attribute]
-    expected: FAIL
-
-  [ariaPressed on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaReadOnly on Element must enqueue an attributeChanged reaction when adding aria-readonly content attribute]
-    expected: FAIL
-
-  [ariaReadOnly on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRelevant on Element must enqueue an attributeChanged reaction when adding aria-relevant content attribute]
-    expected: FAIL
-
-  [ariaRelevant on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRequired on Element must enqueue an attributeChanged reaction when adding aria-required content attribute]
-    expected: FAIL
-
-  [ariaRequired on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRoleDescription on Element must enqueue an attributeChanged reaction when adding aria-roledescription content attribute]
-    expected: FAIL
-
-  [ariaRoleDescription on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRowCount on Element must enqueue an attributeChanged reaction when adding aria-rowcount content attribute]
-    expected: FAIL
-
-  [ariaRowCount on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRowIndex on Element must enqueue an attributeChanged reaction when adding aria-rowindex content attribute]
-    expected: FAIL
-
-  [ariaRowIndex on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaRowSpan on Element must enqueue an attributeChanged reaction when adding aria-rowspan content attribute]
-    expected: FAIL
-
-  [ariaRowSpan on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaSelected on Element must enqueue an attributeChanged reaction when adding aria-selected content attribute]
-    expected: FAIL
-
-  [ariaSelected on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaSetSize on Element must enqueue an attributeChanged reaction when adding aria-setsize content attribute]
-    expected: FAIL
-
-  [ariaSetSize on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaSort on Element must enqueue an attributeChanged reaction when adding aria-sort content attribute]
-    expected: FAIL
-
-  [ariaSort on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueMax on Element must enqueue an attributeChanged reaction when adding aria-valuemax content attribute]
-    expected: FAIL
-
-  [ariaValueMax on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueMin on Element must enqueue an attributeChanged reaction when adding aria-valuemin content attribute]
-    expected: FAIL
-
-  [ariaValueMin on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueNow on Element must enqueue an attributeChanged reaction when adding aria-valuenow content attribute]
-    expected: FAIL
-
-  [ariaValueNow on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
-
-  [ariaValueText on Element must enqueue an attributeChanged reaction when adding aria-valuetext content attribute]
-    expected: FAIL
-
-  [ariaValueText on Element must enqueue an attributeChanged reaction when replacing an existing attribute]
-    expected: FAIL
diff --git a/tests/wpt/meta/html/dom/aria-attribute-reflection.html.ini b/tests/wpt/meta/html/dom/aria-attribute-reflection.html.ini
deleted file mode 100644
index ba427c34c985..000000000000
--- a/tests/wpt/meta/html/dom/aria-attribute-reflection.html.ini
+++ /dev/null
@@ -1,126 +0,0 @@
-[aria-attribute-reflection.html]
-  [role attribute reflects.]
-    expected: FAIL
-
-  [aria-atomic attribute reflects.]
-    expected: FAIL
-
-  [aria-autocomplete attribute reflects.]
-    expected: FAIL
-
-  [aria-busy attribute reflects.]
-    expected: FAIL
-
-  [aria-checked attribute reflects.]
-    expected: FAIL
-
-  [aria-colcount attribute reflects.]
-    expected: FAIL
-
-  [aria-colindex attribute reflects.]
-    expected: FAIL
-
-  [aria-colspan attribute reflects.]
-    expected: FAIL
-
-  [aria-current attribute reflects.]
-    expected: FAIL
-
-  [aria-description attribute reflects.]
-    expected: FAIL
-
-  [aria-disabled attribute reflects.]
-    expected: FAIL
-
-  [aria-expanded attribute reflects.]
-    expected: FAIL
-
-  [aria-haspopup attribute reflects.]
-    expected: FAIL
-
-  [aria-hidden attribute reflects.]
-    expected: FAIL
-
-  [aria-invalid attribute reflects.]
-    expected: FAIL
-
-  [aria-keyshortcuts attribute reflects.]
-    expected: FAIL
-
-  [aria-label attribute reflects.]
-    expected: FAIL
-
-  [aria-level attribute reflects.]
-    expected: FAIL
-
-  [aria-live attribute reflects.]
-    expected: FAIL
-
-  [aria-modal attribute reflects.]
-    expected: FAIL
-
-  [aria-multiline attribute reflects.]
-    expected: FAIL
-
-  [aria-multiselectable attribute reflects.]
-    expected: FAIL
-
-  [aria-orientation attribute reflects.]
-    expected: FAIL
-
-  [aria-placeholder attribute reflects.]
-    expected: FAIL
-
-  [aria-posinset attribute reflects.]
-    expected: FAIL
-
-  [aria-pressed attribute reflects.]
-    expected: FAIL
-
-  [aria-readonly attribute reflects.]
-    expected: FAIL
-
-  [aria-relevant attribute reflects.]
-    expected: FAIL
-
-  [aria-required attribute reflects.]
-    expected: FAIL
-
-  [aria-roledescription attribute reflects.]
-    expected: FAIL
-
-  [aria-rowcount attribute reflects.]
-    expected: FAIL
-
-  [aria-rowindex attribute reflects.]
-    expected: FAIL
-
-  [aria-rowspan attribute reflects.]
-    expected: FAIL
-
-  [aria-selected attribute reflects.]
-    expected: FAIL
-
-  [aria-setsize attribute reflects.]
-    expected: FAIL
-
-  [aria-sort attribute reflects.]
-    expected: FAIL
-
-  [aria-valuemax attribute reflects.]
-    expected: FAIL
-
-  [aria-valuemin attribute reflects.]
-    expected: FAIL
-
-  [aria-valuenow attribute reflects.]
-    expected: FAIL
-
-  [aria-valuetext attribute reflects.]
-    expected: FAIL
-
-  [aria-braillelabel attribute reflects.]
-    expected: FAIL
-
-  [aria-brailleroledescription attribute reflects.]
-    expected: FAIL