From what I remember a company that had a copy of Nintendo's source code for many N64/wii items got hacked and people took a copy of the code. That company was making some sort of portable hand held N64 thing. Apparently Nintendo had copied more into that copy of the repo than they intended and so a bunch of stuff leaked. It was mostly early 2000s stuff.
https://en.wikipedia.org/wiki/2020_Nintendo_data_leak