Does not work anymore, most sites detect that a user-Agent switcher is being used and also some sites refuse to revert because mobile scaling is not in place. You need to update so that when you select a user agent it also scales the resolution of a mobile phone else the site will not go into mobile mode. Does not work until you get some new user-agents, implement automatic resolution scaling so that the page you visit is in a mobile phone resolution and add anti-detection methods. I think this add-on is dead since the developer is no longer responding which is a shame. Hope someone picks up a project like this and makes a better and updated add-on.