Slower moving traffic should be on the right. So to pass someone you should need to move to the left lane. In some states in the US it is also illegal to be in the left lane unneeded, and I known of cops that would use the justification of being in the left lane to pull someone over even if it not illegal.
As far as I known, subsonic is currently closed source and other reimplemented the api with open source programs. Than some people got together to make a standard that was not tied to a closed source programs.
https://opensubsonic.netlify.app/