Which feature below are YOU probing / using in later alignments, as the C datum? The counterbore or the thru hole, and why?
I feel it should be the thru hole, but the arrow is pointing at the larger counterbore, so...???
Arrow is clearly pointing to counterbore. follow the print.
As
KatmandudaMeow says, the counterbore might be the piloting feature or hinge bearing shoulder bolt, and the bore is a thru-hole for a threaded retainer.
Another thing to bring up is that the application of that FCF is part of your question. It's in error. FCF's should be clearly defined and relative to single feature(s) of size, and not implied relevant to multiple features or concentric items. --The Diameter and counterbore should be independently defined and controlled, even if simultaneous application of the same FCF is expected.
I would ask for more information as it's not clearly defined. I agree with
DeWain Hodge, this looks like it could be a clearance hole for a M8 SHCS, but you can't know for sure based on this print. The counterbore has a much larger tolerance on the diameter which implies that it's less important, but the callout is technically pointing at the counterbore. The blank true position callout makes me question the engineer's ability to make a print, so I would just ask for clarification from the customer.
