What firmware does this need?
It doesn't matter. If you're on the original N7 firmware or the latest builds from Google, it still works just fine. I'm now on JOP40C and it works just fine. One update.zip fits all. I do suggest keeping your original file as a backup though as it plays up with OTA updates if you have this mod installed.
You don't need to install this if you are running a CM based firmware (CM10, etc) as I have pushed the patch to the CM repositories and it will be preloaded on your Nexus 7. And no, it's not them stealing credit, I pushed the patch to them.
Video For Your Delectation