Sure, seems useful, I think we could give that a try. I’ve whitelisted all the Guitar Pro file types, you should be able to add them to posts as file uploads.
I think the rule of thumb = this should mainly be used for notation you’ve created. Files you didn’t make yourself but have permission to share are also okay. Beyond that generally best to avoid sharing copyrighted files. (This goes for any uploaded file type, not unique to notation.)
Not sure about a file library but I believe if you do a forum search for a file extension e.g.
.mp3 it’ll return posts including that file type. You can also filter by category; I can see this coming in handy for #show-and-tell / #technique-critique posts!
Just note we’ll probably have to remove if we notice people posting obviously copyrighted stuff e.g. files from other products or otherwise using this as a file sharing site.