It's been a while since we last heard from it, but it seems that Firefox OS is still ongoing. And though the stream of Firefox OS smartphones have slowed down to less than a trickle, there's now a way for you to get a taste of what the platform really has to offer. To some extent, that is. Mozilla has just launched the developer preview of Firefox OS 2.5 for Android phones that you can now install just like a regular app. No need to flash your device just for an appetizer.