What counts as "levy unit"?

[Stiegi]

I was playing as the Kartli and am pretty early into the grand campaign. I was wondering, while leveling one of my generals up, which units fall under the "levy unit" category, that gets buffed through the Drillmaster skill. At first, I thought it will probably be every unit that has "levy"/"levies" in its name. But I compared the stats of two units in that general's army: The "Kavakaza Sparabara" is one of the AoR-unit recruited from the Kartli's starting province, "Kavkasos", and whereas the "Spa" are my faction's own cheap, light spear infantry. Judging purely by the units' melee attack (the melee defense gets altered by other traits), it seems like only the Spa unit counted as a levy unit and got buffed. While both units' melee attack skill is usually at 6, the Spa's melee attack is now at 7, and shows a buffed effect.

So I was wondering, is there any strict rule for which units count as levy units, and get buffed by the Drillmaster skill?

[Stiegi]

Alright, I think I found the answer: When right-clicking on units on the campaign map, it opens a short description of their abilities and stats. For some units, it lists "Levy tier" under "Strength & Weaknesses", which I would assume are all those the levy-buff would apply on. AoR units seem to be described as "Auxiliary" instead, and are therefore not counted as levies. I didn't find any other place where this information was listed, but this makes sense, and might help other people trying to micromanage their generals and their abilities