--- a/addon-sdk/moz.build
+++ b/addon-sdk/moz.build
@@ -76,25 +76,23 @@ modules = [
     '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',
     'sdk/platform/xpcom.js',
-    'sdk/preferences/event-target.js',
     'sdk/preferences/service.js',
     '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/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',

deleted file mode 100644
--- a/addon-sdk/source/lib/sdk/preferences/event-target.js
+++ /dev/null
@@ -1,61 +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": "unstable"
-};
-
-const { Cc, Ci } = require('chrome');
-const { Class } = require('../core/heritage');
-const { EventTarget } = require('../event/target');
-const { Branch } = require('./service');
-const { emit, off } = require('../event/core');
-const { when: unload } = require('../system/unload');
-
-const prefTargetNS = require('../core/namespace').ns();
-
-const PrefsTarget = Class({
-  extends: EventTarget,
-  initialize: function(options) {
-    options = options || {};
-    EventTarget.prototype.initialize.call(this, options);
-
-    let branchName = options.branchName || '';
-    let branch = Cc["@mozilla.org/preferences-service;1"].
-        getService(Ci.nsIPrefService).
-        getBranch(branchName).
-        QueryInterface(Ci.nsIPrefBranch2);
-    prefTargetNS(this).branch = branch;
-
-    // provides easy access to preference values
-    this.prefs = Branch(branchName);
-
-    // start listening to preference changes
-    let observer = prefTargetNS(this).observer = onChange.bind(this);
-    branch.addObserver('', observer);
-
-    // Make sure to destroy this on unload
-    unload(destroy.bind(this));
-  }
-});
-exports.PrefsTarget = PrefsTarget;
-
-/* HELPERS */
-
-function onChange(subject, topic, name) {
-  if (topic === 'nsPref:changed') {
-    emit(this, name, name);
-    emit(this, '', name);
-  }
-}
-
-function destroy() {
-  off(this);
-
-  // stop listening to preference changes
-  let branch = prefTargetNS(this).branch;
-  branch.removeObserver('', prefTargetNS(this).observer);
-  prefTargetNS(this).observer = null;
-}

deleted file mode 100644
--- a/addon-sdk/source/lib/sdk/simple-prefs.js
+++ /dev/null
@@ -1,26 +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 { emit, off } = require("./event/core");
-const { PrefsTarget } = require("./preferences/event-target");
-const { preferencesBranch, id } = require("./self");
-const { on } = require("./system/events");
-
-const ADDON_BRANCH = "extensions." + preferencesBranch + ".";
-const BUTTON_PRESSED = id + "-cmdPressed";
-
-const target = PrefsTarget({ branchName: ADDON_BRANCH });
-
-// Listen to clicks on buttons
-function buttonClick({ data }) {
-  emit(target, data);
-}
-on(BUTTON_PRESSED, buttonClick);
-
-module.exports = target;