Mast holes made by manufacturer

[prebro2]

Stupid question - I have a 1982 27' Catalina. There is hole just below the hole where I pull the line to raise my main sail. I thought there used to be a line coming out of it. The line must have gone to the sky or got pulled too much and gone inside the mast.

Question - what is the purpose of that hole on the port side of the boat? And what should the line that goes thru that hole do?

Thanks,

pres