broken bolt

This isn't my engine but it's the location in question. It's the back of where the oil pan mounts to the engine next to the rear main seal. Where does this hole go? It goes all the way through and doesn't stop like the 1/4" ones. I'm asking because I broke a plastic bolt off in it while trying...

Alright so I was replacing my brake hose as it seemed to be the cause of my caliper sticking. l started to take everything apart but the bolt that holds the flexible rubber hose to the frame was giving me trouble. I ended up getting stripping the head of the torx bolt after only 2 attempts to...