[Mobhack]

Yep - simple checking of the unit class of the unit in question on the formations tab in the database check utilities module would show all formations using it. And the name.

in Mobhack:
File -> check database Utilities

Also see the Mobhack Help section with the same name (you will have to scroll to it or search, its not indexed for some reason)

NB = In the next edition of Mobhack there is a button available for formation or unit data text as well built in - it shows "edit" if formation or unit text exists or "create" if none does. It makes checking and creating those texts much easier since you do not have to manually create them, or manually open coded text files or fire up the game to read them.