Yeah, confusing enough? So these are the dismounted version of the unit "Mounted Cossacks". They basically function like dragoons that can also fight in close combat. I actually think they are the strongest unit option in the Cossack army.
They are a mix of Moloitsy and Skirmishers, with a few Scouts thrown in.
12 stands gives me three full strength (4 stand) units, or four three-stand units. I'll need to finish another three stands of mounted versions before I can use them all though!