It's a mix really, I use musicbutler which takes data from various streaming services along with a few websites & reddit, I make the list for personal use so it's all stuff that I listen to, not terribly comprehensive but I share it anyway
There's nothing to develop unfortunately! It's completely manual, I type out everything, if someone had an automated way of doing it that would be cool though, the old mod here was working on something but hasn't been around in a long time now