While trying to find the source of my oil leak (with no luck so far) I was wiping off some oily grime in that area when my finger hit that bolt and I felt it turn. It was very loose. Looks like it helps connect the engine block to the transaxle. I tightened it down to maybe 30ft-lbs and will check it again in a few days.
Is it something indicative of a bigger problem? Or just sloppy work by the engine swapper(s)? [Hi Randy! ]