Weapon/Mod/Enemy formulas/stats in js/loadout. Interface stuff in js/loadout/views/.
For development js/libs needs:
backbone.js - Backbone, AMD compatible version by James Burke.
underscore.js - Underscore, AMD compatible version by James Burke.
jquery-cookie.js - jquery-cookie by Klaus Hartl.
require.js - RequireJS.
jQuery is loaded from a CDN without defining a protocol (not setting http/https), so using non-server (eg. file://) will probably not work that great.