More information about Firefox OS (B2G) is available here and here. So... I saw this and couldn't resist having a little sneaky play around with it. This is NOT a daily driver. This is NOT stable. It's pre-alpha. If you want something to use as a phone, this isn't it. If you just want to use your phone as a phone, you need android rom.
With that aside, and with the clear understanding that while this won't brick your phone, it's nothing to do with me if it did for some reason, or likewise if your cat (or other cute pet) suffers a painful death as a result of flashing this. At your own risk, like everything else here on XDA-Developers!
So without further ado, WTF is this? Well, it's a project from Mozilla (the lovely people behind the Firefox browser). I won't go into details, suffice to say I suggest you read a lot over at their wiki - start off at https://wiki.mozilla.org/B2G and work your way through the pages.
Instructions for installing the first time :
Wipe data/factory reset
Build 6: -Update code base -Some changes in kernel -A new method of installing data Build 5: -Update code base. This month guys from mozilla have done a lot work on creating your own font and acceleration drawing graphics. Build 4: -Update code base -Volume keys used as a menu button -A new method of installing firmware via recovery -Use ftp server for firmware. Thank you so much for this, ancdix -Small code cleanup -Fix some small bugs Build 3 did not laid out in public. Build 2: -Update code base -Support flash firmware via recovery -Increased performance Build 1: - Initial release