The Tor Browser / file revision

 /* 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/. */

 const {Cu} = require("chrome");

 const ObservableObject = require("devtools/shared/observable-object");

 const {Simulator} = Cu.import("resource://gre/modules/devtools/Simulator.jsm");

 let store = new ObservableObject({versions:[]});

 function feedStore() {

   store.object.versions = Simulator.availableVersions().map(v => {

     return {version:v}

   });

 }

 Simulator.on("register", feedStore);

 Simulator.on("unregister", feedStore);

 feedStore();

 module.exports = store;