After the text-move the black king proceed safely to b6. Both players kept the position closed and soon acquiesced in a draw.
Clearly, the presence of the queen on h4 and that of the bishop on d6 could be an incentive to hit upon this maneuver.
Now the force of the maneuver is immediately clear, and already White is in dire straits.
A remarkable decision! From a Catalan opening the a5-bishop has been pressing against the c7 -pawn, and now Black voluntarily exchanges its defender. However, with this exchange, it becomes more apparent that the a5-bishop is off-side (note that there is no return because earlier White had followed up the bishop's move to a5 with b2-b4) and that Black is a piece up on the kingside. 23...c6 was also an option, keeping ...Bxc3 in reserve.
Black is lining up for a kingside attack, while . . . Nd6-c4 is also a strong positional threat. White next is a blunder, missing Black's main threat.
Without queens the attack remains as strong. White has no defenders and is dead lost.
Black has a spatial advantage, but White finds the best way to activate her queen.
Asking for trouble. 24 . . Kh8 25.Nb6 Qd6 is equal. This was a blitz game . . .