looked under my bike last night, and there's a hole that looks like it's either missing a screw, or there's supposed to be a hole there, for draining or overflow or something. It's an oily hole.
Done some searching, and the manuals and pictures I've seen aren't showing the right angle for this.
If anyone even just knows what this hole is called (see pic), I can look up the rest. If you know if it's supposed to have a screw in there, or why it would have been removed by a previous owner, even better!