Explanation of 11. Kh1 in the Najdorf Amsterdam Variation

I was going through some prep in the Najdorf and I noticed in a lot of variations in the Najdorf Amsterdam Variation (6. f4) and especially in the mainline (6. f4 e5 7. Nf3 Nbd7 8. a4 Qc7 9. Bd3 Be7 10. O-O O-O 11. Kh1), after white castles, white then spends an extra tempo playing Kh1 around the 11th and 12th move. I was wondering what sort of purpose this move serves because Black has no immediate threats along the b6-g1 diagonal and it appears this just wastes a crucial tempo in the opening. Any help is appreciated  

It's not a position where tempo is that important; put the queen on g3 already in this position and White's attack still doesn't crash through. Good piece placement is more important and Kh1 improves the position of the king. On the long run it will be hard to avoid it :  after exf4 and a bishop move, b2 will be hanging, Nd4 may not work because of a pin; or a Nd5 will be not be as strong because the queen will be able to move with check, and so on.

@1
It is a prophylactic move, intended to avoid later tactics along the open diagonal a7-g1.
Likewise after O-O-O white usually plays Kb1 for the same reason.
It also clears g1 for Rf1: sometimes white plays f5, Rg1, g4