diff --git a/static/js/framework/env.js b/static/js/framework/env.js
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+/* Copyright 2016 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 or at
+ * https://developers.google.com/open-source/licenses/bsd
+ */
+
+/**
+ * @fileoverview Defines the type of the CS_env Javascript object
+ * provided by the Codesite server.
+ *
+ * This is marked as an externs file so that any variable defined with a
+ * CS.env type will not have its properties renamed.
+ * @externs
+ */
+
+/** Codesite namespace object. */
+var CS = {};
+
+/**
+ * Javascript object holding basic information about the current page.
+ * This is defined as an interface so that we can use CS.env as a Closure
+ * type name, but it will never be implemented; rather, it will be
+ * made available on every page as the global object CS_env (see
+ * codesite/templates/demetrius/header.ezt).
+ *
+ * The type of the CS_env global object will actually be one of
+ * CS.env, CS.project_env, etc. depending on the page
+ * rendered by the server.
+ *
+ * @interface
+ */
+CS.env = function() {};
+
+/**
+ * Like relativeBaseUrl, but a full URL preceded by http://code.google.com
+ * @type {string}
+ */
+CS.env.prototype.absoluteBaseUrl;
+
+/**
+ * Path to versioned static assets (mostly js and css).
+ * @type {string}
+ */
+CS.env.prototype.appVersion;
+
+/**
+ * Request token for the logged-in user, or null for the anonymous user.
+ * @type {?string}
+ */
+CS.env.prototype.token;
+
+/**
+ * Email address of the logged-in user, or null for anon.
+ * @type {?string}
+ */
+CS.env.prototype.loggedInUserEmail;
+
+/**
+ * Url to the logged-in user's profile, or null for anon.
+ * @type {?string}
+ */
+CS.env.prototype.profileUrl;
+
+/**
+ * CS.env specialization for browsing project pages.
+ * @interface
+ * @extends {CS.env}
+ */
+CS.project_env = function() {};
+
+/** @type {string} */
+CS.project_env.prototype.projectName;