An anonymous reader writes: Mozilla today launched Test Pilot, a program for trying out experimental Firefox features. To try the new functionality Mozilla is offering for its browser, you have to download a Firefox add-on from testpilot.firefox.com and enable an experiment. The main caveat is that experiments are currently only available in English (though Mozilla promises to add more languages "later this year"). Test Pilot was first introduced for Firefox 3.5, but the new program has been revamped since then, featuring three main components: Activity Stream, Tab Center and Universal Search. Activity Stream is designed to help you navigate your browsing history faster, surfacing your top sites along with highlights from your browsing history and bookmarks. Tab Center displays open tabs vertically along the side of your screen. Mozilla says Universal Search "combines the Awesome Bar history with the Firefox Search drop down menu to give you the best recommendations so you can spend less time sifting through search results and more time enjoying the web."