From 61734598002fa81fa1d6d0949f5536ccfdfaba5e Mon Sep 17 00:00:00 2001
From: Oliver Dunk <oliverdunk@google.com>
Date: Mon, 10 Aug 2026 14:18:04 +0000
Subject: [PATCH] Define Browser interface

Defines the Browser interface so that it can be
referenced from other specifications which define
WebExtension APIs.

Also, update heading levels for other content to
correctly create table of contents.
---
 specification/window.browser.bs | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/specification/window.browser.bs b/specification/window.browser.bs
index 52621cb0a..d2ef00e7b 100644
--- a/specification/window.browser.bs
+++ b/specification/window.browser.bs
@@ -42,11 +42,23 @@ spec: html; urlPrefix: https://html.spec.whatwg.org/multipage/
   and are left up to User Agent implementation.
 </section>
 
+<section>
+  <h2 id="browser-interface">{{Browser}}</h2>
+
+  <pre class="idl">
+    [Exposed=(Window,Worker), LegacyNoInterfaceObject]
+    interface Browser {
+      // Intentionally left blank.
+    };
+  </pre>
+
+  Note: This interface is intentionally left blank to allow APIs to be exposed by other specifications.
+</section>
 
   <section>
-    <h3 id="window-interface">
+    <h2 id="window-interface">
       <a attribute lt="browser"><code>window.browser</code></a> API
-    </h3>
+    </h2>
 
     {{browser}} is UA defined attribute exposed on {{window}}. When implemented,
     it MUST be used only for WebExtension related functionality.
@@ -89,15 +101,15 @@ spec: html; urlPrefix: https://html.spec.whatwg.org/multipage/
 
 <pre class="idl">
   partial interface Window {
-   attribute object browser;
+   attribute Browser browser;
   };
 
 </pre>
 
   <section>
-    <h3 id="worker-interface">
+    <h2 id="worker-interface">
       Worker API
-    </h3>
+    </h2>
 
     When {{browser}} is defined on {{window}}, it SHOULD also be exposed on {{ServiceWorkerGlobalScope}}
     of origins associated with WebExtensions.
@@ -106,6 +118,6 @@ spec: html; urlPrefix: https://html.spec.whatwg.org/multipage/
 
 <pre class="idl">
   partial interface ServiceWorkerGlobalScope {
-    attribute object browser;
+    attribute Browser browser;
   };
 </pre>