Firefox already has several builds made to test out experimental features, but now you can take some of them for a spin even if you only have the stable browser. Mozilla has re-launched Test Pilot for Firefox, an add-on it first released in 2009 to study how people interacted with their browser. This one comes with three features the team is still in the midst of developing. First is Activity Stream, which turns every new tab into a home-page-slash-news-feed that displays the newest posts from your top websites. It also highlights some of the pages you've bookmarked.
The second feature called Tab Center functions like OneTab and other similar third-party add-ons. It displays all your open tabs on the left-hand side of the browser for easy access. Finally, Universal Search gives you recommendations right on the address bar as you type. According to VentureBeat, Mozilla decided to launch Test Pilot to be able to gather more data and feedback about its newest features from more people. If you'd like to try it out yourself, just go to Test Pilot's official website on Firefox and click "Get Started."