I worked on a couple of Xbox games when the Xbox was around. You didn't get much concrete information about it even as part of the official docs. Plenty of stuf

I worked on a couple of Xbox games when the Xbox was around. You didn't get much concrete information about it even as part of the official docs. Plenty of stuff about the performance characteristics and memory layout for texture/vertex/index data, but nothing low level. I think there might have been enough exposed by D3D to let you bypass it entirely, at least in theory, but you'd have been on your own when it came to figuring out the ins and outs of what needed to go in the FIFO... I vaguely recall somebody from MS saying on the Xbox developer newsgroups that providing the full information wasn't part of their deal with NVidia, and that was that.