I've got a screw loose!

[danimal2]

O.k. it's not really loose. Maybe missing though? Please take a look at the photo below. I've been battling an oil leak issue and just replaced my spark plug tube orings. They were definitely bad, but not sure the complete cause of my issue.

Right by the crank case breather hose is a screw hole. It's threaded, but there's nothing in it. Not sure what it's purpose in life is and whether it shook itself out and is supposed to be there, or nothing to concern myself with.

Does anybody know what this is for if anything. Or maybe check your bike and see if you have anything in that hole, or if it's empty like mine? Can't get a good look inside to see if there's a bottom to it. or if it goes through.