At first this looks like a standard example of Morphy's Mate (with discovered mate) as the rook is moved back down the g-file but that doesn't work because of 3...Nxb2. That's why you have to play 3.Rg8++ & then Rg1# (after sweeping away any blocking pieces).
It's not so much the attached comment as the move 3.Rxh7 itself that makes little sense to me - why would anyone even consider it ? It blows a hole in the mating net that you can't easily repair !
Typo error in the book perhaps ?
Unless my mind is totally on the fritz and I'm missing something, there's a glaring error in the first puzzle of The Power of the Capture Check. See Move 3 and the variation below for my explanation.
Thanks.