I asked elsewhere whether or not this was the true absolute correct way to back up your playlists and songs, and never got a straight answer. So that's why it's not in the FAQ.
Oh. What was sideways about the answers you got? Backing up the contents of the "fids" directories (one per drive) certainly backs up all the songs and all the playlists and all their attached "static" or permanent information (the tags for artist, album, auto-repeat, auto-shuffle etc.).
It does not back up the "dynamic" or writable information (play count and last played), or the other data not related to individual songs or playlists (bookmarks, tuner presets, equaliser settings, owner's name, configured IP address).
The only other thing to know, is that after restoring a backup of the "fids" directories, you'll have to remove the three files database, playlists, and tags from the /drive0/var directory to force a database rebuild. (You have to do this whenever you fiddle with the fids without Emplode/Emptool/JEmpeg knowing.)
Peter