Hey all, I’m working on my girlfriends fc and i noticed this hole to the left of the water pump. i dont see a hose that would fit it, so im curious as to what this is for

 

That's the air inlet for the Air Control Valve (part of the emission/smog air injection system). Looks like the air pump (which would have been mounted right about where you're holding the phone) is long gone. It would have had a short hose connected from the back of the pump to that opening.