This Plater Mod changes the level text of the arena unit / arena pet to the relevant unit number, instead of the level. In case the unit is not an arena unit or arena pet, it simply hides the number instead (e.g., Mirror Images).
Note: This is a WotLK Classic Plater Mod, although it may also work for Retail WoW.
Note: This Mod only switches the level text, it does not hide the name of the unit. See my other mod https://wago.io/iCrqwNc4y for this behaviour.