Reported: GoMMO Studio treats MAUs as creatures and reads their effects from Monster.ini instead of Unit.ini.
Found: The model viewer lists MAUs with the monsters and NPCs, and the only creature effect table it read was Monster.ini, so a MAU showed none of its own effects. Unit.ini is also keyed differently from the other tables: each id is a MAU part, by slot (head, upper, lower, arms, shoulder, back) and that part's row.
Fix: The model viewer now reads Unit.ini for MAUs, the way the game client does, so each part shows its own effects. It covers the RF 4.55, Age of Patron and Golden Age clients. This is a GoMMO Studio change, released separately from the RF 4.55 server, and it ships in the next GoMMO Studio release.
MAUs still appear under the Monsters and NPCs tab of the model browser; a tab of their own is a separate change.