f3 is the English attack.
Did you see Yermolinsky's analysis of the game?
Very often both moves, f3 and Be3, can be played together; combined with Qd2 and g4, they form one of the main attacking blueprints for white in the Najdorf. The English Attack has always been popular, but some players have leaned towards alternate move orders (6. f3, 6. h3, etc.) to avoid variations where black can play Ng4 in an attempt to swap minor pieces. The opening in general lends itself to quick knock-outs because of the unbalanced pawn structure and frequent castling on opposite sides. Be3 and f3 are part of the same attacking plan though, so it's difficult to suggest one over the other. It would be more logical to compare variations like 6. Be3 and 6. f4 for example, since then white's bishop can no longer reach the kingside easily.
The English attack is the same attacking scheme, but then against the Sicilian Dragon where black has weakened his king side pawn structure.
Therefor is there a difference. It was told me that this attacking scheme was not at its best against the Najdorf, because in the Najdorf are the king side pawns still at their original place. As a result did I change my play against the Najdorf back to old Fisher like Bc4. So I was surprised to see this attacking scheme against the Najdorf used by Caruana and even more how crushing his attack was.
I mean I saw Caruana Playing It against Gelfand At tata steel chess, and he just destroyed gelfand in 30 moves !!