Puzzle 64040

From game #1zLbnFcM
Where is the gain of advantage?
I see the threat by pushing the pawn, 30. h4 ...
But, why play 30. ... Rb1?
Why try to force to move Rf1 off of the "f" column?

lichess.org/training/64040

It's a good question. Some kind of weird computer move. Nothing Black can do to stop 2. h5 otherwise and sometimes the "horizon effect" enters in to computer calculations. Obviously you play 2. Rxb1 and the inevitable h5 is postponed for a move. Computers do stuff like this. Just do the next puzzle!

It's an exchange sacrifice. Give a rook and get a Bishop by playing the now possible 32... Qf3. Then Black has to trade Queens to avoid mate and the resulting ending is winning for White.