Describe manifest update behavior

index.html

@@ -842,11 +842,12 @@ <h3>
           application, it SHOULD treat that manifest as a description of a
           distinct application, even if it is served from the same URL as that
           of another application. When the user agent sees a manifest where
-          |manifest|["id"] [=url/equal|equals=] the [=identity=] of an
-          already-installed application, it SHOULD be used as a signal that
-          this manifest is a replacement for the already-installed
-          application's manifest, and not a distinct application, even if it is
-          served from a different URL than the one seen previously.
+          |manifest|["id"] is [=url/equal=] with [=URL serializer/exclude
+          fragment|exclude fragment true=] to the [=identity=] of an
+          already-installed application, it SHOULD be used as a signal that this
+          manifest is a replacement for the already-installed application's
+          manifest, and not a distinct application, even if it is served from a
+          different URL than the one seen previously.
         </p>
         <p class="note">
           The [=identity=] can be used by a service that collects lists of web
@@ -1293,6 +1294,13 @@ <h3>
             <li>[=Process the `id` member=] passing |json|, |manifest| and
             |document URL|.
             </li>
+            <li>
+              If the [=document=]'s [=document|processed
+              manifest=] is not null, and [=document=]'s [=document|processed
+              manifest=]'s id is not
+              [=URL/equal=] with [=URL serializer/exclude fragment|exclude fragment true=] to |manifest|["id"],
+              return.
+            </li>
             <li>[=Process the `scope` member=] passing |json|, |manifest|, and
             |manifest URL|.
             </li>
@@ -1421,7 +1429,19 @@ <h3 id="applying">
           <h3>
             Updating the manifest
           </h3>
-          <aside class="issue" data-number="446"></aside>
+          <p>
+            For installed web application, the manifest is fetched and processed
+            on every page load. When the processing is successful, user agents
+            MAY apply updated manifest to any current and future <a>application
+            contexts</a>
+            associated with the application. 
+          </p>
+          <p>
+            User agents SHOULD be careful about performing update to manifest
+            fields like app name and icons. Users should be fully aware if
+            such fields are to be be updated to avoid web applications being
+            installed and silently changed to appear as a different one.
+          </p>
         </section>
       </section>
     </section>