All copyrighted material is stripped from the repos and has to be extracted from a valid rom by the user.
The reverse engineered code doesn’t count as derivative.
Super Mario 64 has been decompiled for years now.
I am not a lawyer so can’t comment on the reverse engineered code counting as derivative. Personally, I thought it would be considered that. The time doesn’t mean much considering Yuzu.
Yuzu | Initial release | January 14, 2018; 6 years ago |