This includes the Chrome 16 release notes.

chrome/common/extensions/docs/static/manifest.html

 <div id="pageData-name" class="pageData">Formats: Manifest Files</div>
 <div id="pageData-showTOC" class="pageData">true</div>
 
 <p>
 Every extension, installable web app, and theme has a
 <a href="http://www.json.org">JSON</a>-formatted manifest file,
 named <code>manifest.json</code>,
 that provides important information.
 </p>
 
@@ skipping 32 matching lines @@
   "<a href="#homepage_url">homepage_url</a>": "http://<em>path/to/homepage</em>",
   "<a href="#incognito">incognito</a>": "spanning" <em>or</em> "split",
   "<a href="#key">key</a>": "<em>publicKey</em>",
   "<a href="#minimum_chrome_version">minimum_chrome_version</a>": "<em>versionString</em>",
   "<a href="#nacl_modules">nacl_modules</a>": [...],
   "<a href="#offline_enabled">offline_enabled</a>": true,
   "<a href="omnibox.html">omnibox</a>": { "keyword": "<em>aString</em>" },
   "<a href="options.html">options_page</a>": "<em>aFile</em>.html",
   "<a href="#permissions">permissions</a>": [...],
   "<a href="npapi.html">plugins</a>": [...],
+  "<a href="#requirements">requirements</a>": {...},
   "<a href="autoupdate.html">update_url</a>": "http://<em>path/to/updateInfo</em>.xml"
 }
 </pre>
 
 
 <h2>Field details</h2>
 
 <p>
 This section covers fields that aren't described in another page.
 For a complete list of fields,
@@ skipping 535 matching lines @@
 </tr>
 <tr>
   <td> "webRequestBlocking" </td>
   <td> Required if the extension uses the
        <a href="webRequest.html">chrome.webRequest</a> module in a blocking
        fashion. </td>
 </tr>
 </tr>
 </table>
 
+<h3 id="requirements">requirements</h3>
+
+<p>
+Technologies required by the app or extension.
+Hosting sites such as the Chrome Web Store may use this list
+to dissuade users from installing apps or extensions
+that will not work on their computer.
+</p>
+
+<p>
+The only supported requirement is "3D",
+which denotes GPU hardware acceleration.
+For that requirement,
+you can list the 3D-related features your app requires,
+as demonstrated in the following example:
+</p>
+
+<pre>
+"requirements": {
+  "3D": {
+    "features": ["css3d", "webgl"]
+  }
+}
+</pre>
+
+<p>
+The "css3d" requirement refers to the
+<a href="http://www.w3.org/TR/css3-3d-transforms/">CSS 3D Transforms specification</a>,
+and the "webgl" requirement refers to the
+<a href="http://www.khronos.org/webgl/">WebGL API</a>.
+For more information on Chrome 3D graphics support,
+see the help article on
+<a href="http://www.google.com/support/chrome/bin/answer.py?answer=1220892">WebGL and 3D graphics</a>.
+Support for additional requirements checks may be added in the future.
+</p>
+
 
 <h3 id="version">version</h3>
 
 <p>
 One to four dot-separated integers
 identifying the version of this extension.
 A couple of rules apply to the integers:
 they must be between 0 and 65535, inclusive,
 and non-zero integers can't start with 0.
 For example, 99999 and 032 are both invalid.
@@ skipping 31 matching lines @@
 A missing integer is equal to zero.
 For example, 1.1.9.9999 is newer than 1.1.
 </p>
 
 <p>
 For more information, see
 <a href="autoupdate.html">Autoupdating</a>.
 </p>
 
 <!-- [PENDING: Possibly: point to the store/dashboard and make a big deal of the fact that autoupdating is free if you use them.] -->