1 e4, f4?

I faced this opening - the Duras Gambit - recently on Lichess. I don't know why someone would play it since there isn't really good compensation for the lost pawn. It didn't appear to be a mouse slip either because the opponent seemed somewhat prepared. 

The game didn't last long. I played pretty calmly and the opponent ended up blundering. 

Have you ever faced this move? If so, share it if you want

I've never faced it but I feel like the idea is to castle kingside and open up the rook and start an attack with that (the open f-fille is really the only benefit). Other than that I have no idea why you would play this lol.

and also to play d4 and open up the light-squared bishop I guess.

That's a good assessment. I wonder if a YouTuber recommends it