Firefox for Windows 8 Metro under development by Mozilla

Mozilla developers already have a lot on their plates. In addition to dealing with shorter release cycles for Firefox and Thunderbird, they’re now looking after tablet and smartphone versions of Firefox for Android, Firefox Home on iOS, and there’s a new long-term support version of Firefox, too. On top of that, they’re starting work on a Metro version of Firefox for Windows 8.

The Foundation plans on having the first test builds ready to go before summer, with alpha and beta releases slated for some time during the second half of 2012. Getting Firefox re-tooled using the WinRT programming model is important as it will allow Mozilla to submit the browser to the Windows Store, which will be front-and-center in Windows 8 — and will quickly become the destination for Windows users who are hunting for new software.

Firefox for Metro will be built with full-screen use in mind and a UI that’s focused on touch interaction. It will also support Windows 8′s 1/6th and 5/6 screen-snap sizes — which allow users to view multiple apps on the Metro desktop at the same time. Mozilla’s Asa Dotzler also proposes building in Live Tile support, feeding information like the presence of Firefox friends and Firefox Home updates, as well as the option to add additional tiles to the Start Screen for web apps that run inside Firefox.

Will competing browsers have Metro offerings, too? Google certainly has the resources to put together a Chrome remaster. It’s all but certain that Opera will offer an immersive app as well, since already offers a version of its browser that’s customized for Windows tablets. The Windows Store presents a significant opportunity for alternative browsers to attract new users, so expect to see these three pop up on its digital shelves.

Mozilla will take any new users it can get, what with Firefox’s user share slipping steadily as Google Chrome’s stock continues to rise.