I've been waiting for this since I first got acquainted with arcade emulators - 2013. Apparently, it's said the truth - when you really expect something, it'll happen sooner or later. And I see already the expected negative voices about that. 😁
Therefore, I have a suggestion - perhaps it makes sense to add a filters for MAME Home Brew and traditional MAME / ARCADE64 ROMs (similar as Available / Unavailable, Originals / Clones, etc.).
Robert, I remember that you were against that, but under such circumstances, now I would like even more to see an additional audit type in ARCADE64 - ROM groups' audit. That's, if the ROM group is incomplete, 'cause some clone or original is missing entirely, the emulator will notify about that.