I played a game where I had a rook pawn left and my opponent had only his bishop which controlled the queening square. I flagged and the server awarded a win to my opponent. While I can construct a helpmate, I thought that strictly speaking, a lone bishop should be considered insufficient mating material and helpmates using the flagged player’s material should not come into consideration.
As long as a mating position can be constructed on the board, regardless of the most horrible moves required, it’s a loss.
If it was a USCF rated tournament game then 14E2 would support a draw. If FIDE rules were in use then 6.10 would support a win by the lone K+B.