@chris I've since done further research. I'll just post links, not in order:
https://www.youtube.com/watch?v=v-iRW7BAoOU
https://web.archive.org/web/20221018151339/https://www.twitlonger.com/show/n_1sruqo3
https://www.libretro.com/index.php/category/swanstation/
https://github.com/libretro/swanstation
https://www.reddit.com/r/RetroArch/comments/no50r1/duckstation_vs_swanstation/
Stenzek was worried about others commercialising DuckStation; if it were me, I'd be honoured, but hey.
I run my own projecct, Libreboot, that I even sell, but I also have competitors. I compete by being better than them, while remaining libre.
@chris Interesting; look at the screenshot. This is from running "git shortlog -sne" on duckstation.git (master branch).
Quite a number of authors, and most of the commits aren't even Stenzek.
Therefore, Stenzek is violating the GPL.
I will be doing further auditing, and probably getting in contact with Stenzek myself in due course.
EDIT: I realised Connor Mclaughlin is stenzek. There are still many authors though, whose copyright is being violated.