Menu code documentation

Is there a more in depth docs for the menu code? Their is one example of adding a menu item and variable, which btw needs to be updated, but more of an architecture document. I am trying to add a add to playlist option to the quick menu. I have gotten so far by looking at the playlist settings functionality but instead ofy display list showing the dynamic menu I copied from there, I am getting a folder explorer. I am kind of trying to get the list of playlists to show up.