This reads like an AI response to me.
Mac OS has never used X11 as a primary display system. Apple had a version they supplied with older Mac OS X versions for people using older Unix applications (and half-arsed ports) but that’s been unsupported since 2012. You can still install the modern “XQuartz” open source equivalent, but it’s still secondary.
That repo is an amazing example of something so well documented as to how it works they completely neglected to have even a paragraph explaining what it really does and why I would want to use it.
As far as I can tell it’s a Spotify connect client which runs as a daemon so you probably need to control it remotely? Kinda like how AirPlay works on apple devices? Is that right?