I've contacted the support crew asking for help about MM missing support to sync with Philips GoGear HDD070/00 mp3 player, and they told me they have no means of supporting it directly, but will accept any plugin developed by outsiders.
The player is a very old one, and stores playlists into an SQL file (references HERE), and came with native support only on a modded version of MusicMatch Jukebox and, later on, on Sveta Portable.
A little freeware app, Herbert, actually supports syncing with it, but I would like to be able to use MM....any volunteers for some help in developing a dedicated plugin? (I'm no coder but I learn fast....)