--- a/addon-sdk/moz.build
+++ b/addon-sdk/moz.build
@@ -33,28 +33,25 @@ modules = [
     'sdk/addon/window.js',
     'sdk/base64.js',
     'sdk/browser/events.js',
     'sdk/clipboard.js',
     'sdk/console/plain-text.js',
     'sdk/console/traceback.js',
     'sdk/content/events.js',
     'sdk/content/loader.js',
-    'sdk/content/mod.js',
     'sdk/content/thumbnail.js',
-    'sdk/content/utils.js',
     'sdk/core/disposable.js',
     'sdk/core/heritage.js',
     'sdk/core/namespace.js',
     'sdk/core/observer.js',
     'sdk/core/promise.js',
     'sdk/core/reference.js',
     'sdk/deprecated/api-utils.js',
     'sdk/deprecated/events/assembler.js',
-    'sdk/deprecated/sync-worker.js',
     'sdk/deprecated/unit-test-finder.js',
     'sdk/deprecated/unit-test.js',
     'sdk/deprecated/window-utils.js',
     'sdk/dom/events-shimmed.js',
     'sdk/dom/events.js',
     'sdk/event/chrome.js',
     'sdk/event/core.js',
     'sdk/event/dom.js',
@@ -70,17 +67,16 @@ modules = [
     'sdk/io/stream.js',
     'sdk/io/text-streams.js',
     'sdk/lang/functional.js',
     'sdk/lang/functional/concurrent.js',
     'sdk/lang/functional/core.js',
     'sdk/lang/functional/helpers.js',
     'sdk/lang/type.js',
     'sdk/lang/weak-set.js',
-    'sdk/loader/sandbox.js',
     'sdk/messaging.js',
     'sdk/model/core.js',
     'sdk/net/url.js',
     'sdk/net/xhr.js',
     'sdk/notifications.js',
     'sdk/output/system.js',
     'sdk/passwords.js',
     'sdk/passwords/utils.js',
@@ -90,18 +86,16 @@ modules = [
     'sdk/preferences/utils.js',
     'sdk/private-browsing.js',
     'sdk/private-browsing/utils.js',
     'sdk/querystring.js',
     'sdk/request.js',
     'sdk/self.js',
     'sdk/simple-prefs.js',
     'sdk/simple-storage.js',
-    'sdk/stylesheet/style.js',
-    'sdk/stylesheet/utils.js',
     'sdk/system.js',
     'sdk/system/environment.js',
     'sdk/system/events-shimmed.js',
     'sdk/system/events.js',
     'sdk/system/globals.js',
     'sdk/system/process.js',
     'sdk/system/runtime.js',
     'sdk/system/unload.js',

deleted file mode 100644
--- a/addon-sdk/source/lib/sdk/stylesheet/style.js
+++ /dev/null
@@ -1,69 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-"use strict";
-
-module.metadata = {
-  "stability": "experimental"
-};
-
-const { Class } = require("../core/heritage");
-lazyRequire(this, "../url", "isLocalURL");
-lazyRequire(this, "./utils", "loadSheet", "removeSheet", "isTypeValid");
-lazyRequire(this, "../lang/type", "isString");
-const { attachTo, detachFrom } = require("../content/mod");
-lazyRequire(this, '../self', "data");
-
-const { freeze, create } = Object;
-
-function Style({ source, uri, type }) {
-  source = source == null ? null : freeze([].concat(source));
-  uri = uri == null ? null : freeze([].concat(uri));
-  type = type == null ? "author" : type;
-
-  if (source && !source.every(isString))
-    throw new Error('Style.source must be a string or an array of strings.');
-
-  if (uri && !uri.every(isLocalURL))
-    throw new Error('Style.uri must be a local URL or an array of local URLs');
-
-  if (type && !isTypeValid(type))
-    throw new Error('Style.type must be "agent", "user" or "author"');
-
-  return freeze(create(Style.prototype, {
-    "source": { value: source, enumerable: true },
-    "uri": { value: uri, enumerable: true },
-    "type": { value: type, enumerable: true }
-  }));
-};
-
-exports.Style = Style;
-
-attachTo.define(Style, function (style, window) {
-  if (style.uri) {
-    for (let uri of style.uri)
-      loadSheet(window, data.url(uri), style.type);
-  }
-
-  if (style.source) {
-    let uri = "data:text/css;charset=utf-8,";
-
-    uri += encodeURIComponent(style.source.join(""));
-
-    loadSheet(window, uri, style.type);
-  }
-});
-
-detachFrom.define(Style, function (style, window) {
-  if (style.uri)
-    for (let uri of style.uri)
-      removeSheet(window, data.url(uri));
-
-  if (style.source) {
-    let uri = "data:text/css;charset=utf-8,";
-
-    uri += encodeURIComponent(style.source.join(""));
-
-    removeSheet(window, uri, style.type);
-  }
-});

deleted file mode 100644
--- a/addon-sdk/source/lib/sdk/stylesheet/utils.js
+++ /dev/null
@@ -1,75 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-"use strict";
-
-module.metadata =  {
-  "stability": "experimental"
-};
-
-const { Ci } = require("chrome");
-
-const SHEET_TYPE = {
-  "agent": "AGENT_SHEET",
-  "user": "USER_SHEET",
-  "author": "AUTHOR_SHEET"
-};
-
-function getDOMWindowUtils(window) {
-  return window.QueryInterface(Ci.nsIInterfaceRequestor).
-                getInterface(Ci.nsIDOMWindowUtils);
-};
-
-/**
- * Synchronously loads a style sheet from `uri` and adds it to the list of
- * additional style sheets of the document.
- * The sheets added takes effect immediately, and only on the document of the
- * `window` given.
- */
-function loadSheet(window, url, type) {
-  if (!(type && type in SHEET_TYPE))
-    type = "author";
-
-  type = SHEET_TYPE[type];
-
-  if (url instanceof Ci.nsIURI)
-    url = url.spec;
-
-  let winUtils = getDOMWindowUtils(window);
-  try {
-    winUtils.loadSheetUsingURIString(url, winUtils[type]);
-  }
-  catch (e) {};
-};
-exports.loadSheet = loadSheet;
-
-/**
- * Remove the document style sheet at `sheetURI` from the list of additional
- * style sheets of the document.  The removal takes effect immediately.
- */
-function removeSheet(window, url, type) {
-  if (!(type && type in SHEET_TYPE))
-    type = "author";
-
-  type = SHEET_TYPE[type];
-
-  if (url instanceof Ci.nsIURI)
-    url = url.spec;
-
-  let winUtils = getDOMWindowUtils(window);
-
-  try {
-    winUtils.removeSheetUsingURIString(url, winUtils[type]);
-  }
-  catch (e) {};
-};
-exports.removeSheet = removeSheet;
-
-/**
- * Returns `true` if the `type` given is valid, otherwise `false`.
- * The values currently accepted are: "agent", "user" and "author".
- */
-function isTypeValid(type) {
-  return type in SHEET_TYPE;
-}
-exports.isTypeValid = isTypeValid;