e4 e5 c4 Nf6 d3?

I was playing a game with a schoolmate and they played this interesting opening as white. Does anybody know the name for it? It seems strong (ignoring that the game ended in a terrible blunder xD)

I doubt it has a name but it looks like an attempt at a Stonewall.  If you look under English/Reversed Sicilian (ECO A10/A20) lines with a sequence of 1. c4 e5 2. d3 Nf6 you might find more.

I believe this opening is a variation of the English opening called the Whale. At least that's what game explorer says if you put the moves e4, e5, c4 into it. I think black is better off replying 2...Nc6 as it makes d4 harder for white...

I believe white is playing the Bavarian Gambit. The proper second move for black is d5. This challenges white for control of the center squares and forces white to decide whether to be strong left or be strong right. It also impacts upon which side white will castle.

white can play just about anything, but putting the pawns in that way is not a try for an opening advantage.

This variation or you can say this setup /system is called botvinik system named after Mikhail botvinik. It is can be played by moving 1.c4 as the first move or by the move 1.e4 also. I am searching about this particular variation now.