Amazon has made the Android-based source code of the Kindle Fire available for download. It’s quite large — over 800 megabytes — and won’t be of any use to casual users. It will, however, enable some custom builds of the software and ROM hacking in the future. Naturally, lots of the Kindle Fire is not, in fact, open source development. What they’re releasing is likely (no one has taken a close look just yet) the heavily modified Android 2.2 code on which their custom OS is based.