Having worked (very) closely on GPU firmwares and drivers, I always find it funny that it is still something so closely guarded and protected. Honestly there isn't much to it. That's fairly regular code, not like futuristic algorithms. You won't find any novel rasterizing code or ways to order your commands or whatever, 99% of the interesting work is done by the GPU. You'll find basic or vaguely clever code to order lists and optimize the order of the commands, but that's it.

I'm 95% sure that if AMD released their firmware and/or their drivers source code, NVidia wouldn't learn anything of value, they wrote the same stuff anyway. That's just sad \o/