Also, how much space do they take up, compared to the highest practical quality music file? Like, can you convert them to FLAC or opus, and see how they compare?
Hmm you’re right about the links. Funnily enough, I did look for WikiPedia articles of those and couldn’t find them.
As far as file size goes, that’s part of why I like them so much. PSF files are between 100-300k.