It's a threaded hole used for fixing appropriate engine hangers when removing the engine assembly from the engine bay and is right next to the main oil gallery plug/hole.
Source of the oil?
There could be a hairline crack or something similiar in the threaded hole/short block and since it's right on the top of the oil gallery, there could be some oil seeping out -> clean the hole and close it with a suitable plug (sadly, I don't know the size/pitch of the thread) and examine if it solves the oil contamination.
Or a wrench monkey played around your engine bay and contaminated this area with an oily residue
