London trick | Puzzle of the day 03/12/2023

Hey guys! In the puzzle of the day, how can Black gain material from White's "automatic" London system?

e5 dxe5 dxe5 then maybe white realizes that if they play Nxe5 they lose a piece during the trades, so they play Bg3, to save the bishop, then black plays e4 winning a piece with a pawn fork