for/else is unfortunately named (although makes sense if you think about the hidden if/else in a loop). It is essentially use to distinguish between "this loop ended naturally" (the else condition) or "this loop was broken".

I used it recently in some mutating code in which I wanted to make a change, and also know if it did actually make a change. If the routine gets to the end of the loop without finding a place to make a change, it hits the "else" and returns False.