Chess960: two move ideas no. 6

Here black equalises by realising that the e5 square is completely safe for the queen. The idea even accelerates kingside castling. Black's idea is very similar to idea no.3 in this blog:

SP37 white to play: try to see black's ideas

Enjoy 960

Hint: dxe5, Qxe5, f4?! Black also sees that a1/b2 are weak squares
Note: there is a big difference between 1.d4...e5 and 1.f4...e5. This is because after 1.f4 and a pawn exchange, black's queen on e5 is no longer safe from white's threat Nb3/d4.