what opening is this for white?

Some sort of time-warp Sicilian Grand Prix attack, where white is bailed out of choosing a poor opening by the fact that black allows him to take two consecutive moves.

I assume the moves went:

1.e4 c5

2.f4 e6

3.Nf3 (pass)?!

4.Bc4

please disregard second diagram.

sequence of moves as follows-

1.e4 c5

2.Bc4 e6

3.f4 Nc6

4.Nf3

It's a Grand Prix, at least the correct one with Nc6.

exd5 obviously hasn't happened yet because black hasn't played d5. Often g6 is played next and white castles and prepares things like Qe1 with a swift kingside attack to follow.

as a beginner i'm not too familiar with many book openings  and tend to use what i know works (reasonably well), this opening was the result of responses to opponents moves and i've used it many times since.this allows for e5-after d3,Nc3,Be3 in no particular order.

I've a friend who is a very good grand prix player and I'll point him to this thread when he gets home from work this evening for elucidation.

Apparently the chess.com explorer calls the 2. Nc3 xxx 3.f4 move order the B25 closed sicilian, but after f4 it's simply a grand prix by transposition to avoid Tal gambit lines with the immediate 2...d5.