contol lines mainsail, lancer 30
I am wondering if one is an outhaul, and the other two are reefing lines. The reefing lines would be attached through stainless rings sewn or pressed into the leech of the main. One would probably be about 2 feet or so up from the clew, while the second ring would be another couple of feet above that. These become the clew when you are reefed. There should be corresponding rings sewn into the luff, which become the new tack when reefing. These lines are probably run through the boom going forward where they would exit to turning blocks, maybe at the mast step, and run back towards the cockpit, typically passing through line stoppers which are used so that 1 winch can be used for several functions.
It is possible on a 30 footer, that the reefing lines exit the boom mid cockpit and you just use brute force when reefing at the clew. In this case you would find some cleats mounted on the boom near the exit slots.
It is also possible this main has three reef points, though two is more common.