Oh! Author of the project here, but not op. Happy to answer any questions.
The code for the Museum as well as the Webamp player that powers the interactive preview can be found here: https://github.com/captbaritone/webamp
You can also find a blog post I wrote about the project here: https://jordaneldredge.com/winamp-skin-musuem/
I have a question: It seems that all the preview PNGs and the WSZ files themselves are fetched from hxxp://webampskins.org. When I go to that website directly, I get redirected to some shady looking website pushing crypto and gambling. Can you give me some background about this?