Before the final version of Firefox OS hits, Mozilla wants developers to start making apps, so it's selling smartphones running the new OS. (You can also install Firefox OS on your Android phone using these instructions.)
A company called Geeksphone makes the device. There's no price listed yet.
Like Android, Firefox OS is open sourced, meaning developers can download it for free and customize it.
Ubuntu, another open mobile OS, will launch later this year.
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