This is presumably what they mean: https://imgur.com/bPFmcSp https://imgur.com/bPFmcSp The square to the bottom right of the Queen isn't "currently" visible to

This is presumably what they mean: https://imgur.com/bPFmcSp https://imgur.com/bPFmcSp The square to the bottom right of the Queen isn't "currently" visible to the bishop, but if the Queen moved into that square they'd still be killed by the bishop.