Merge pull request #382 from w3c/file_ext

Drop .json as standard file ext. (closes #381)

index.html

@@ -182,7 +182,7 @@ <h3>
 &lt;title&gt;Store finder - search&lt;/title&gt;
 
 &lt;!-- Startup configuration --&gt;
-&lt;link rel="manifest" href="manifest.json"&gt;
+&lt;link rel="manifest" href="manifest.webmanifest"&gt;
 
 &lt;!-- Fallback application metadata for legacy browsers --&gt;
 &lt;meta name="application-name" content="Store Finder"&gt;
@@ -1599,7 +1599,7 @@ <h3>
           <p>
             For example, if the <var>value</var> of <code>start_url</code> is
             <samp>../start_point.html</samp>, and the manifest's URL is
-            <samp>https://example.com/resources/manifest.json</samp>, then the
+            <samp>https://example.com/resources/manifest.webmanifest</samp>, then the
             result of <a>URL parsing</a> would be
             <samp>https://example.com/start_point.html</samp>.
           </p>
@@ -2745,7 +2745,7 @@ <h3>
                 File extension(s):
               </dt>
               <dd>
-                .json, .webmanifest
+                .webmanifest
               </dd>
               <dt>
                 Macintosh file type code(s):