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 is supposed to help Mozilla figure out which features should ship and how they should work, by letting users provide feedback and suggestions to the teams behind each one. You can turn each experiment on and off at any time (there will be bugs, so this will naturally come in handy), and the add-on explains what information you’re sharing with Mozilla to help the team understand how the feature is used.