Help me understand this Steinitz move?

Here's a game between Steinitz and Czarnowski: lichess.org/study/nR7KhaGo

The move I'm having the most trouble understanding is 11.h3

The reason the move came as a surprise to me is that it weakens the dark squares around the King, and that both the Black Queen and Bishop are eyeing the h2 square. In the game, Steinitz opted for a queenside attack starting on move 12, so I don't think 11.h3 was part of that attack. Therefore, I'm thinking 11.h3 was a defensive move. However, I don't see what threat 11.h3 is addressing. Why didn't White launch his queenside attack immediately with 11.Ne2 instead of playing h3 first?

Thanks in advance for looking at this interesting game with me!

Hey h3 is played becouse black is putting pressure on h2 so knight from f3 cant move , also h3 prevents ng4 where white would lose his dark bishop.

Thanks for your reply. I understand preventing ng4 to protect the dark square Bishop, but I still don't understand how h3 relieves the pressure on the h2 square. After h3, the Bishop and Queen are still looking at the h2 square.

Yes but theres no pawn on h2 anymore ... so theres nothing to take :)

If you play h3 then you have nothing to take on h2, your Knight on f3 is free to go away without having to be a slave of h2.., see how the Queen on c7 and the bishop on d6 control the square f4 and a pawn on h6 protects the square g5 so with h3 you're getting rid of Ng4 which might take your pair of bishops. (As the position is open you want to keep your bishops, that represents a little advantage in terms of mobility, usually in close positions you'd rather a Knight).

Another caracteristic of moves like h3 is that you're giving room to your king which migth be useful in the future when a rook comes to the 1st rank.

Sometimes people play h3 as a waiting move instead of defining their positions.

Hope that makes sense.

Thank both of you for your helpful comments! I appreciate it

h3 is only to protect the dark square bishop from ...Ng4. 11 Ne2 Ng4 were good for black.
The pressure on h2 can often be ignored. White can play with Nf3 and on Bxh2+ Kh1 black has won an insignificant rook pawn and black's bishop is misplaced. It is different of course is the bishop were at b8 instead of d6.