If the attacking king has already reached the sixth rank while the pawn is still far back, the defender can still hold by checking from behind, but the king must first step aside to avoid a back-rank mate.
White's king has already reached d6, which Philidor's rook-on-the-sixth method would have prevented. Is Black lost? No. Because the pawn is still back on e4, it offers the white king no shelter, and checks from behind are enough to hold. This is the second method, discovered by Karstedt more than a century after Philidor.