AFAIK, the original XBOX was always based on a heavily stripped-down win2k kernel, and evolved very little. The "API" games used was a jump table to kernel functions, everything ran in kernel-space. I don't know much about later consoles, but I wouldn't be surprised if they used the same generic architecture.
https://xboxdevwiki.net/Kernel that site has quite a bit of info, with ongoing reverse-engineering and clean-room reimplementation projects (reactos, xquemu)
Re:Windows XP source code has leaked
by google234123 on Monday September 28, 2020 @02:54AM
(#24613693)
reactos being clean is a funny joke
I'm very curious to see more come out as the code is picked apart piece by piece, and whether or not it'll confirm my suspicions. I'm also very interested in that Xbox folder, with any luck it'll be time to dust off my old OG Xbox and do some hacking!