Mozilla re-introduces it Test Pilot for Firefox, a plugin that allows anyone to test the experimental features and report their impressions.
The Test Pilot first introduced for Firefox 3.5, but now the updated program contains three key components: Activity Stream, Tab Center, and Universal Search.
The Activity Stream aims to make your browsing history searchable faster, which Mozilla believes will help you find important ones websites and view contents faster. When you open a new tab, Activity Stream checks your top sites from your browsing history and their bookmarks you.
The Tab Center it's pretty simple: it displays open tabs vertically and along its left side screens and not horizontally and at the top of the window.
As far as Universal Search Mozilla says it "combines history with the Search drop down menu to give you the best recommendations so you spend less time finding what you want through searching results. "
Currently Test Pilot is available in English, and you can download it via it testpilot.firefox.com