diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index a6556cb39..7895a1662 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -2751,6 +2751,10 @@ interface SerialPortRequestOptions {
     filters?: SerialPortFilter[];
 }
 
+interface SetHTMLOptions {
+    sanitizer?: Sanitizer | SanitizerConfig | SanitizerPresets;
+}
+
 interface ShadowRootInit {
     clonable?: boolean;
     customElementRegistry?: CustomElementRegistry | null;
@@ -14142,6 +14146,12 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setAttributeNodeNS)
      */
     setAttributeNodeNS(attr: Attr): Attr | null;
+    /**
+     * The **`setHTML()`** method of the Element interface provides an XSS-safe method to parse and sanitize a string of HTML and insert it into the DOM as a subtree of the element.
+     *
+     * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setHTML)
+     */
+    setHTML(html: string, options?: SetHTMLOptions): void;
     /**
      * The **`setHTMLUnsafe()`** method of the Element interface is used to parse HTML input into a DocumentFragment, optionally filtering out unwanted elements and attributes, and those that don't belong in the context, and then using it to replace the element's subtree in the DOM.
      *
@@ -17987,7 +17997,7 @@ interface HTMLElementEventMap extends ElementEventMap, GlobalEventHandlersEventM
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement)
  */
-interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement {
+interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /**
      * The **`HTMLElement.accessKey`** property sets the keystroke which a user can press to jump to a given element.
      *
@@ -20312,7 +20322,10 @@ declare var HTMLOptionsCollection: {
     new(): HTMLOptionsCollection;
 };
 
-interface HTMLOrSVGElement {
+interface HTMLOrSVGElement extends HTMLOrSVGOrMathMLElement {
+}
+
+interface HTMLOrSVGOrMathMLElement {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/autofocus) */
     autofocus: boolean;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/dataset) */
@@ -24036,7 +24049,7 @@ interface MathMLElementEventMap extends ElementEventMap, GlobalEventHandlersEven
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MathMLElement)
  */
-interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGOrMathMLElement {
     addEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
@@ -26033,6 +26046,7 @@ declare var NavigationPreloadManager: {
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition)
  */
 interface NavigationTransition {
+    /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition/committed) */
     readonly committed: Promise<void>;
     /**
      * The **`finished`** read-only property of the NavigationTransition interface returns a Promise that fulfills at the same time the navigatesuccess event fires, or rejects at the same time the navigateerror event fires.
@@ -31828,7 +31842,7 @@ interface SVGElementEventMap extends ElementEventMap, GlobalEventHandlersEventMa
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/SVGElement)
  */
-interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /** @deprecated */
     readonly className: any;
     /**
diff --git a/baselines/ts5.5/dom.generated.d.ts b/baselines/ts5.5/dom.generated.d.ts
index e1e2ad25d..760d5f162 100644
--- a/baselines/ts5.5/dom.generated.d.ts
+++ b/baselines/ts5.5/dom.generated.d.ts
@@ -2748,6 +2748,10 @@ interface SerialPortRequestOptions {
     filters?: SerialPortFilter[];
 }
 
+interface SetHTMLOptions {
+    sanitizer?: Sanitizer | SanitizerConfig | SanitizerPresets;
+}
+
 interface ShadowRootInit {
     clonable?: boolean;
     customElementRegistry?: CustomElementRegistry | null;
@@ -14129,6 +14133,12 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setAttributeNodeNS)
      */
     setAttributeNodeNS(attr: Attr): Attr | null;
+    /**
+     * The **`setHTML()`** method of the Element interface provides an XSS-safe method to parse and sanitize a string of HTML and insert it into the DOM as a subtree of the element.
+     *
+     * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setHTML)
+     */
+    setHTML(html: string, options?: SetHTMLOptions): void;
     /**
      * The **`setHTMLUnsafe()`** method of the Element interface is used to parse HTML input into a DocumentFragment, optionally filtering out unwanted elements and attributes, and those that don't belong in the context, and then using it to replace the element's subtree in the DOM.
      *
@@ -17971,7 +17981,7 @@ interface HTMLElementEventMap extends ElementEventMap, GlobalEventHandlersEventM
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement)
  */
-interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement {
+interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /**
      * The **`HTMLElement.accessKey`** property sets the keystroke which a user can press to jump to a given element.
      *
@@ -20291,7 +20301,10 @@ declare var HTMLOptionsCollection: {
     new(): HTMLOptionsCollection;
 };
 
-interface HTMLOrSVGElement {
+interface HTMLOrSVGElement extends HTMLOrSVGOrMathMLElement {
+}
+
+interface HTMLOrSVGOrMathMLElement {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/autofocus) */
     autofocus: boolean;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/dataset) */
@@ -24012,7 +24025,7 @@ interface MathMLElementEventMap extends ElementEventMap, GlobalEventHandlersEven
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MathMLElement)
  */
-interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGOrMathMLElement {
     addEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
@@ -26009,6 +26022,7 @@ declare var NavigationPreloadManager: {
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition)
  */
 interface NavigationTransition {
+    /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition/committed) */
     readonly committed: Promise<void>;
     /**
      * The **`finished`** read-only property of the NavigationTransition interface returns a Promise that fulfills at the same time the navigatesuccess event fires, or rejects at the same time the navigateerror event fires.
@@ -31803,7 +31817,7 @@ interface SVGElementEventMap extends ElementEventMap, GlobalEventHandlersEventMa
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/SVGElement)
  */
-interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /** @deprecated */
     readonly className: any;
     /**
diff --git a/baselines/ts5.6/dom.generated.d.ts b/baselines/ts5.6/dom.generated.d.ts
index be2edd668..f62c5468e 100644
--- a/baselines/ts5.6/dom.generated.d.ts
+++ b/baselines/ts5.6/dom.generated.d.ts
@@ -2748,6 +2748,10 @@ interface SerialPortRequestOptions {
     filters?: SerialPortFilter[];
 }
 
+interface SetHTMLOptions {
+    sanitizer?: Sanitizer | SanitizerConfig | SanitizerPresets;
+}
+
 interface ShadowRootInit {
     clonable?: boolean;
     customElementRegistry?: CustomElementRegistry | null;
@@ -14139,6 +14143,12 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setAttributeNodeNS)
      */
     setAttributeNodeNS(attr: Attr): Attr | null;
+    /**
+     * The **`setHTML()`** method of the Element interface provides an XSS-safe method to parse and sanitize a string of HTML and insert it into the DOM as a subtree of the element.
+     *
+     * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setHTML)
+     */
+    setHTML(html: string, options?: SetHTMLOptions): void;
     /**
      * The **`setHTMLUnsafe()`** method of the Element interface is used to parse HTML input into a DocumentFragment, optionally filtering out unwanted elements and attributes, and those that don't belong in the context, and then using it to replace the element's subtree in the DOM.
      *
@@ -17984,7 +17994,7 @@ interface HTMLElementEventMap extends ElementEventMap, GlobalEventHandlersEventM
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement)
  */
-interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement {
+interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /**
      * The **`HTMLElement.accessKey`** property sets the keystroke which a user can press to jump to a given element.
      *
@@ -20309,7 +20319,10 @@ declare var HTMLOptionsCollection: {
     new(): HTMLOptionsCollection;
 };
 
-interface HTMLOrSVGElement {
+interface HTMLOrSVGElement extends HTMLOrSVGOrMathMLElement {
+}
+
+interface HTMLOrSVGOrMathMLElement {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/autofocus) */
     autofocus: boolean;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/dataset) */
@@ -24033,7 +24046,7 @@ interface MathMLElementEventMap extends ElementEventMap, GlobalEventHandlersEven
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MathMLElement)
  */
-interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGOrMathMLElement {
     addEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
@@ -26030,6 +26043,7 @@ declare var NavigationPreloadManager: {
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition)
  */
 interface NavigationTransition {
+    /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition/committed) */
     readonly committed: Promise<void>;
     /**
      * The **`finished`** read-only property of the NavigationTransition interface returns a Promise that fulfills at the same time the navigatesuccess event fires, or rejects at the same time the navigateerror event fires.
@@ -31825,7 +31839,7 @@ interface SVGElementEventMap extends ElementEventMap, GlobalEventHandlersEventMa
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/SVGElement)
  */
-interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /** @deprecated */
     readonly className: any;
     /**
diff --git a/baselines/ts5.9/dom.generated.d.ts b/baselines/ts5.9/dom.generated.d.ts
index 24a34aa36..769e447f2 100644
--- a/baselines/ts5.9/dom.generated.d.ts
+++ b/baselines/ts5.9/dom.generated.d.ts
@@ -2748,6 +2748,10 @@ interface SerialPortRequestOptions {
     filters?: SerialPortFilter[];
 }
 
+interface SetHTMLOptions {
+    sanitizer?: Sanitizer | SanitizerConfig | SanitizerPresets;
+}
+
 interface ShadowRootInit {
     clonable?: boolean;
     customElementRegistry?: CustomElementRegistry | null;
@@ -14139,6 +14143,12 @@ interface Element extends Node, ARIAMixin, Animatable, ChildNode, NonDocumentTyp
      * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setAttributeNodeNS)
      */
     setAttributeNodeNS(attr: Attr): Attr | null;
+    /**
+     * The **`setHTML()`** method of the Element interface provides an XSS-safe method to parse and sanitize a string of HTML and insert it into the DOM as a subtree of the element.
+     *
+     * [MDN Reference](https://developer.mozilla.org/docs/Web/API/Element/setHTML)
+     */
+    setHTML(html: string, options?: SetHTMLOptions): void;
     /**
      * The **`setHTMLUnsafe()`** method of the Element interface is used to parse HTML input into a DocumentFragment, optionally filtering out unwanted elements and attributes, and those that don't belong in the context, and then using it to replace the element's subtree in the DOM.
      *
@@ -17984,7 +17994,7 @@ interface HTMLElementEventMap extends ElementEventMap, GlobalEventHandlersEventM
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement)
  */
-interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement {
+interface HTMLElement extends Element, ElementCSSInlineStyle, ElementContentEditable, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /**
      * The **`HTMLElement.accessKey`** property sets the keystroke which a user can press to jump to a given element.
      *
@@ -20309,7 +20319,10 @@ declare var HTMLOptionsCollection: {
     new(): HTMLOptionsCollection;
 };
 
-interface HTMLOrSVGElement {
+interface HTMLOrSVGElement extends HTMLOrSVGOrMathMLElement {
+}
+
+interface HTMLOrSVGOrMathMLElement {
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/autofocus) */
     autofocus: boolean;
     /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/HTMLElement/dataset) */
@@ -24033,7 +24046,7 @@ interface MathMLElementEventMap extends ElementEventMap, GlobalEventHandlersEven
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/MathMLElement)
  */
-interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface MathMLElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGOrMathMLElement {
     addEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | AddEventListenerOptions): void;
     addEventListener(type: string, listener: EventListenerOrEventListenerObject, options?: boolean | AddEventListenerOptions): void;
     removeEventListener<K extends keyof MathMLElementEventMap>(type: K, listener: (this: MathMLElement, ev: MathMLElementEventMap[K]) => any, options?: boolean | EventListenerOptions): void;
@@ -26030,6 +26043,7 @@ declare var NavigationPreloadManager: {
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition)
  */
 interface NavigationTransition {
+    /** [MDN Reference](https://developer.mozilla.org/docs/Web/API/NavigationTransition/committed) */
     readonly committed: Promise<void>;
     /**
      * The **`finished`** read-only property of the NavigationTransition interface returns a Promise that fulfills at the same time the navigatesuccess event fires, or rejects at the same time the navigateerror event fires.
@@ -31825,7 +31839,7 @@ interface SVGElementEventMap extends ElementEventMap, GlobalEventHandlersEventMa
  *
  * [MDN Reference](https://developer.mozilla.org/docs/Web/API/SVGElement)
  */
-interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement {
+interface SVGElement extends Element, ElementCSSInlineStyle, GlobalEventHandlers, HTMLOrSVGElement, HTMLOrSVGOrMathMLElement {
     /** @deprecated */
     readonly className: any;
     /**
diff --git a/inputfiles/patches/html.kdl b/inputfiles/patches/html.kdl
index 112f9ff15..5155f2030 100644
--- a/inputfiles/patches/html.kdl
+++ b/inputfiles/patches/html.kdl
@@ -197,6 +197,15 @@ interface SharedWorker {
   }
 }
 
+// Hack to avoid breakage due to the mixin renaming to HTMLOrSVGOrMathMLElement
+interface-mixin HTMLOrSVGElement extends=HTMLOrSVGOrMathMLElement
+interface HTMLElement {
+    includes HTMLOrSVGElement
+}
+interface SVGElement {
+    includes HTMLOrSVGElement
+}
+
 removals {
   dictionary CanvasRenderingContext2DSettings {
     member colorType // Blink-only as of 2025-12, being tested in WebKit
diff --git a/inputfiles/patches/webauthn.kdl b/inputfiles/patches/webauthn.kdl
index d0f167b59..9e994354e 100644
--- a/inputfiles/patches/webauthn.kdl
+++ b/inputfiles/patches/webauthn.kdl
@@ -14,33 +14,41 @@ removals {
     // https://searchfox.org/mozilla-central/source/dom/webidl/WebAuthentication.webidl
     // https://searchfox.org/wubkat/source/Source/WebCore/Modules/webauthn/AuthenticationExtensionsClientInputs.idl
     // https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/modules/credentialmanagement/authentication_extensions_client_inputs.idl
-    member appidExclude
-    member credBlob
-    member getCredBlob
-    member hmacGetSecret // No implementation as of 2025-05
-    member payment
+    member appidExclude // Blink only as of 2026-05
+    member credBlob // Blink only as of 2026-05
+    member getCredBlob // Blink only as of 2026-05
+    member hmacGetSecret // No implementation as of 2026-05
+    member payment // Blink test only as of 2026-05
+    member remoteClientDataJSON // No implementation as of 2026-05
   }
 
   dictionary AuthenticationExtensionsClientInputsJSON {
-    member appidExclude
+    member appidExclude // Blink only as of 2026-05
+    member remoteClientDataJSON // No implementation as of 2026-05
   }
 
   dictionary AuthenticationExtensionsClientOutputs {
     // (same as *Inputs)
-    member appidExclude // No implementation as of 2025-05
-    member hmacGetSecret // No implementation as of 2025-05
-    member payment // Blink only as of 2025-06
+    member appidExclude // No implementation as of 2026-05
+    member hmacGetSecret // No implementation as of 2026-05
+    member payment // Blink only as of 2026-05
+    member remoteClientDataJson // No implementation as of 2026-05
+  }
+
+  dictionary AuthenticationExtensionsClientOutputsJSON {
+    member appidExclude // No implementation as of 2026-05
+    member remoteClientDataJson // No implementation as of 2026-05
   }
 
   dictionary PublicKeyCredentialCreationOptions {
     member attestationFormats // Blink only as of 2024-08
     member hints // Blink only as of 2024-08
   }
-  
+
   dictionary PublicKeyCredentialCreationOptionsJSON {
     member attestationFormats // Gecko only as of 2024-08
   }
-  
+
   dictionary PublicKeyCredentialRequestOptions {
     member hints // Blink only as of 2024-08
   }
@@ -56,8 +64,4 @@ removals {
     member otp
     member password
   }
-
-  dictionary AuthenticationExtensionsClientOutputsJSON {
-    member appidExclude // No implementation as of 2025-12
-  }
 }
diff --git a/inputfiles/removedTypes.jsonc b/inputfiles/removedTypes.jsonc
index 8634c0968..291459ed9 100644
--- a/inputfiles/removedTypes.jsonc
+++ b/inputfiles/removedTypes.jsonc
@@ -200,11 +200,8 @@
             "RequestInit": {
                 "members": {
                     "member": {
-                        "adAuctionHeaders": null, // Blink only as of 2023-11
-                        "attributionReporting": null, // Blink only as of 2023-10
                         "duplex": null, // Blink only as of 2023-09
                         "privateToken": null, // Blink only as of 2023-09
-                        "sharedStorageWritable": null, // Blink only as of 2023-10
                         "targetAddressSpace": null // Blink only as of 2023-09
                     }
                 }
diff --git a/package-lock.json b/package-lock.json
index 09f59ab7a..04d44388d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -331,9 +331,9 @@
       }
     },
     "node_modules/@mdn/browser-compat-data": {
-      "version": "7.3.14",
-      "resolved": "https://registry.npmjs.org/@mdn/browser-compat-data/-/browser-compat-data-7.3.14.tgz",
-      "integrity": "sha512-Mqll0z0todYcAOqr+2hnYZRFe7+CwyU14lj86vzAGDJVeqnp618ybGzwHTI7sxyhd/46FFtJAlZNUmL1YHSX+Q==",
+      "version": "7.3.15",
+      "resolved": "https://registry.npmjs.org/@mdn/browser-compat-data/-/browser-compat-data-7.3.15.tgz",
+      "integrity": "sha512-8YoG52J2ZsR+T4p0JsAuoWeztBgJsAtGY+LeGEAHvyJBojJzJtLb8o1fRsIbc0v6EHKRLIrCU3VoAIK1olntag==",
       "dev": true,
       "license": "CC0-1.0"
     },
@@ -1074,9 +1074,9 @@
       ]
     },
     "node_modules/@webref/css": {
-      "version": "8.5.4",
-      "resolved": "https://registry.npmjs.org/@webref/css/-/css-8.5.4.tgz",
-      "integrity": "sha512-3t4LuTww0lNpJRi3k/Obb74xWc9+YVGcO0DNoc5k3+dmqIklcj3KHKBk4GHMwj4+zMwJXLpK7F2R9r3qTZg2Ag==",
+      "version": "8.5.5",
+      "resolved": "https://registry.npmjs.org/@webref/css/-/css-8.5.5.tgz",
+      "integrity": "sha512-i6R7FkwHJTK74VwMvul3V9rYN9Dq3NzJinaKadtg7DkMtvOwTuB5ZR3zGGCWr+nh7jcftymoThr3gKbBnvo3Hg==",
       "dev": true,
       "license": "MIT",
       "peerDependencies": {
@@ -1091,16 +1091,16 @@
       "license": "MIT"
     },
     "node_modules/@webref/events": {
-      "version": "1.22.1",
-      "resolved": "https://registry.npmjs.org/@webref/events/-/events-1.22.1.tgz",
-      "integrity": "sha512-UUypBtgLviCHkPxkigj0vclgG+gYIoHpLSvk05nXBFDMSiDOwPJjK66OkCh0hjiDG/dMzzUz1D1ngzJTU9OEEQ==",
+      "version": "1.23.0",
+      "resolved": "https://registry.npmjs.org/@webref/events/-/events-1.23.0.tgz",
+      "integrity": "sha512-q0R3pFzvfYuXW+GN8nJMzZL9NoS+cOb4G/s4qBzuWRceGhfMpYFdCsVr+i84X1/dkYslYpQ8qxhSCcbxk8PFew==",
       "dev": true,
       "license": "MIT"
     },
     "node_modules/@webref/idl": {
-      "version": "3.76.0",
-      "resolved": "https://registry.npmjs.org/@webref/idl/-/idl-3.76.0.tgz",
-      "integrity": "sha512-3HPoiu2bN9UmfdIUi5+qH9oBBQmhfccOmoUXSlwEmv7LvDu1ifmGSzkUCRrYYsVubMeZCMSLRMXnWDFn2K6qBw==",
+      "version": "3.77.0",
+      "resolved": "https://registry.npmjs.org/@webref/idl/-/idl-3.77.0.tgz",
+      "integrity": "sha512-XpDJ471ryn5pq2Z8wXnOd10XxiT6Nnp0QTrxgcU1cdvHBLEvbsmSj/d5ldnp90e1vyxllKyt53Ztl0/0DnKuHw==",
       "dev": true,
       "license": "MIT",
       "peerDependencies": {
diff --git a/src/build/emitter.ts b/src/build/emitter.ts
index a05c088b3..6a92e4e0f 100644
--- a/src/build/emitter.ts
+++ b/src/build/emitter.ts
@@ -1516,7 +1516,7 @@ export function emitWebIdl(
     for (const i of allNonCallbackInterfaces.sort(compareName)) {
       if (i.legacyNamespace) {
         continue;
-      } else if (i.noInterfaceObject) {
+      } else if (i.noInterfaceObject || i.mixin) {
         emitInterface(i);
       } else {
         emitInterface(i);
diff --git a/src/build/expose.ts b/src/build/expose.ts
index 09c7d2345..4c0c023c0 100644
--- a/src/build/expose.ts
+++ b/src/build/expose.ts
@@ -288,6 +288,8 @@ function flattenType(type: Browser.Typed[]) {
 function isEmptyMixin(i?: Browser.Interface) {
   return (
     !!i?.mixin &&
+    // (extends can only happen by patches)
+    !i.extends &&
     isEmptyRecord(i.properties?.property) &&
     isEmptyRecord(i.methods?.method) &&
     isEmptyRecord(i.constants?.constant) &&
diff --git a/src/build/helpers.ts b/src/build/helpers.ts
index 4a211d4ae..bb3a476ea 100644
--- a/src/build/helpers.ts
+++ b/src/build/helpers.ts
@@ -148,7 +148,7 @@ export function merge<T>(
           ) {
             target[k] = srcProp;
           } else {
-            if (targetProp === srcProp && k !== "name") {
+            if (targetProp === srcProp && !["name", "mixin"].includes(k)) {
               console.warn(
                 `Redundant merge value ${targetProp} in ${JSON.stringify(src)}`,
               );
diff --git a/src/build/patches.ts b/src/build/patches.ts
index 86a4a3af6..f779fafb1 100644
--- a/src/build/patches.ts
+++ b/src/build/patches.ts
@@ -281,6 +281,7 @@ function handleMixinAndInterfaces(
   };
   return {
     name,
+    ...(type === "mixin" ? { mixin: true } : {}),
     ...optionalNestedMember("events", event, { event }),
     ...optionalNestedMember("properties", property, { property }),
     ...optionalNestedMember("methods", method, { method }),
@@ -539,7 +540,7 @@ function convertForRemovals(obj: unknown): unknown {
   if (obj && typeof obj === "object") {
     const newObj: Record<string, unknown> = {};
     for (const [key, value] of Object.entries(obj)) {
-      if (key !== "name") {
+      if (!["name", "mixin"].includes(key)) {
         const cleaned = convertForRemovals(value);
         // (intentionally covers null too)
         if (typeof cleaned === "object") {
diff --git a/src/build/widlprocess.ts b/src/build/widlprocess.ts
index d8b5ddeb2..beed49ae0 100644
--- a/src/build/widlprocess.ts
+++ b/src/build/widlprocess.ts
@@ -119,7 +119,6 @@ function convertInterfaceMixin(
 ) {
   const result = convertInterfaceCommon(i, commentMap);
   result.mixin = true;
-  result.noInterfaceObject = true;
   return result;
 }