Docserver: there is only one.

chrome/common/extensions/docs/static/js/branch.js

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-(function() {
-
-function init() {
-  var branchChooser = document.getElementById('branch-chooser-popup');
-  Array.prototype.forEach.call(branchChooser.getElementsByTagName('button'),
-                               function(button) {
-    button.addEventListener('click', function(event) {
-      choose(button.className);
-      event.stopPropagation();
-    });
-  });
-}
-
-function choose(branch) {
-  var currentBranch = window.bootstrap.branchInfo.current;
-  var path = window.location.pathname.split('/');
-  if (path[0] == '')
-    path = path.slice(1);
-  var index = path.indexOf(currentBranch);
-  if (index != -1)
-    path[index] = branch;
-  else
-    path.splice(0, 0, branch);
-  window.location.pathname = '/' + path.join('/');
-}
-
-init();
-
-})()