My first guess was Youtube API + youtubedl/ffmpeg. But after cross-checking some results at least source "b" isn't youtube. If you just check for unusual song t

My first guess was Youtube API + youtubedl/ffmpeg. But after cross-checking some results at least source "b" isn't youtube. If you just check for unusual song titles like "testtest" you'll see that there are other sites which are getting the same results, so it's probably just indexing a couple of these shady sites to get the results. I highly doubt there's some kind of API behind this you could use in your project.