Okay I made one that saves sounds. The code is actually very simple, it does the usual create a link download element and clicks it, and this time it simply sets the href to the source of the html audio element referred by a sound.
https://snap.berkeley.edu/snap/snap.html#present:Username=pumpkinhead&ProjectName=save-media
Good thing the browser (or at least Chrome (and Firefox)) automatically appends the correct file extension if you don't provide one. So I didn't have to worry about detecting what file format the sound was. (I know how you can do: that there's some text in the beginning of the sound data URL that says something like "mpeg" or "wav")
(side note how do i get it to open the file dialog like it does in firefox in chrome because sometimes i just want to open the file)