I don't know and it's not something I've ever found a need to bother with. Sure, wdDoc.Range.Find.Execute only evaluates to a Boolean, but that's not the point. The point is that, if it evaluates to True, the current range changes to the found range.
I'd have thought it pretty obvious that, since the range the .Find is working on is wdDoc.Range, that's the range that I was referring to.