chromium/chrome/test/data/extensions/api_test/login_screen_apis/update_manifest.xml

<?xml version='1.0' encoding='UTF-8'?>
<!--
  This update manifest points to the ./extension.crx and
  ./in_session_extension.ctx files. "mock.http" is a  placeholder that gets
  substituted with the test server address in runtime.
-->
<gupdate xmlns='http://www.google.com/update2/response' protocol='2.0'>
  <app appid='oclffehlkdgibkainkilopaalpdobkan'>
    <updatecheck
        codebase='http://mock.http/extensions/api_test/login_screen_apis/extension.crx'
        version='1.28' />
  </app>
  <app appid='ofcpkomnogjenhfajfjadjmjppbegnad'>
    <updatecheck
        codebase='http://mock.http/extensions/api_test/login_screen_apis/in_session_extension.crx'
        version='0.8' />
  </app>
</gupdate>