(another) puzzle I do not understand

lichess.org/training/61705
the solution is: f6, bxf6, rxf6. But after kxf6, Qxf6, the exchange has been rook+pawn for a knight and a bishop.
Ok, the black King is under pressure, etc., etc. but... is this a puzzle!?

Perhaps the puzzle should continue since the next move for white will be Ne6 with check and a discover attack on the rook on h8. This is why the computer suggests for black d5 so that the rook is not lost but exchanged against the white knight. Next white can continue with some checks and grab pawns. I think there are interesting lines to consider to understand the position but the puzzle stops before you actually play them...

what are you talking about.. white is up a piece..

@Manglecopter sorry I do not understand what you mean

Not much to learn from this puzzle , except that you train your calculation skills....