Can't help but feel that you're barking up a somewhat nonexistent tree here. This project is for interfacing with the deprecated Spotify CarThing. If you don't know about it, you're very likely not their target audience, so I think it's pretty fine if you don't get it. If you do know what the CarThing is, the readme intro covers what this project does pretty well.

In similar vein, you wouldn't expect a Javascript library readme to start by explaining what Javascript is or what a software library is, but if you didn't know those things, you would feel equally lost.