The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

    http://creativecommons.org/publicdomain/zero/1.0/ */

 const { interfaces: Ci, classes: Cc } = Components;

 function startup(aParams, aReason) {

   Components.utils.import("resource://gre/modules/Services.jsm");

   let res = Services.io.getProtocolHandler("resource")

                        .QueryInterface(Ci.nsIResProtocolHandler);

   res.setSubstitution("browser_dbg_addon4", aParams.resourceURI);

   // Load a JS module

   Components.utils.import("resource://browser_dbg_addon4/test.jsm");

 }

 function shutdown(aParams, aReason) {

   // Unload the JS module

   Components.utils.unload("resource://browser_dbg_addon4/test.jsm");

   let res = Services.io.getProtocolHandler("resource")

                        .QueryInterface(Ci.nsIResProtocolHandler);

   res.setSubstitution("browser_dbg_addon4", null);

 }