White: Please explain.

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Jion_Wansu

It's called resign

Fear_ItseIf

they saw the mate then had a lapse in concentration and played the move anyway. there is no follow up.

Arraskrahe

there is no mate in 1. Only the rook hanging on h8 before the castle. the king can go to d7. Of course black would be lost anyway if he lost the rook.

ProfBlunderer

I think that before blunder white is better: two pieces for a rock, bishop pair and g6 weakened dark squares near the black king, because there isn't black bishop.