In this balanced position, one of the best players of the world from the last century and even an analyst of the ex-world champion Robert James Fischer came up with a very interesting strategic idea: trade the fianchettoed bishop for the centralized knight on e5.
Larsen is right to consider that doubling the pawns on the e-file is fine since the white dark-squared bishop will not be strong and Black will have nice control over the center and the open f-file.
And we need to be fast now since White is now threatening to play Qg4 once the e5-pawn is protected by the rook.
White tries to protect the e5-pawn, but now we can clearly see how the black knight is superior to the white bishop.
This move is very strong! The white queen should keep an eye on f2. That is why Qd2 is mandatory. The problem for White is that when the knight arrives to e5 later, f3 will be easier to access!
Capturing the e5-pawn with the knight in the next move and we can see how the light squares are extremely weak. Black is much better.