>As for CVS, whoa, that old? That means that technically, Nintendo could have everything a year after SMB? That's freaking wild
I doubt they were using it all the way back then. Judging from the leaked source code of the SNES and GameBoy games as well as a batch file hidden in the FDS BIOS, they were programmed and compiled on DOS. CVS is primarily a Unix program. N64 devkits run a Unix-like OS called Irix so it makes sense for them to use that and they probably stuck with that ever since.

>And it's kind of wild that Nintendo will practically the only Japanese dev that still has all this shit. Square apparently doesn't even have the Kingdom Heart source code and that was on freaking PS2
Well given that most Japanese games are developed for consoles, they probably assume that any re-release is going to be done via emulation and leaving source code is just opening themselves for leaks like this. So they just delete the source code. I guess Nintendo just assumed that they had better security or just took cues from Western devs preserving source code.