Yamaha 1300 Tourer - Yamaha 1300 Tourer Fansite

I noticed today that there is a little seepage around the drain cock. It's not enough to drip on the floor but I can see it on the bottom of the engine. Question, what is this thing for? I know some of you are saying what? It's on the bottom of the engine, probably chrome, held with two bolts. It's got a little hole in the middle of it.

Hutch