Clarify "Browser Policy APIs" to be extension APIs

... as per Henri

index.html

@@ -190,14 +190,14 @@ <h2 id="implementation">Building A Secure Web with W3C Standards</h2>
         preserve security more robustly, such as certain uses of Subresource Integrity [[SRI]].
     </p></dd>
 
-    <dt>Browser Policy APIs</dt>
+    <dt>Browser Policy Extension APIs</dt>
     <dd><p>
         Similarly, adopting "https://" makes the practice of imposing policy in intermediaries
         (e.g., in schools and workplaces, by parents, in prisons) more difficult. While TLS
         Man-in-the-Middle is one solution to this, it is a blunt one, sacrificing substantial
         security when they are used. Therefore, we encourage development of facilities to enable
         imposition of policy -- when it is necessary -- in a more controlled way, e.g., as new APIs
-        in Web browsers.
+        for Web browser extensions.
     </p><dd>
 
     <dt>Documentation of Best Practices</dt>