The objective of this move is not very clear, and I understand why it has never been played before. But, to be honest, it's not so bad and the pawn can be useful on a4 at some point, either to prevent b7-b5 or to play a5 to gain space. In any case, Black responds with a move that is equally practical and enigmatic.
1. g2g3  1... d7d5  2. f1g2  2... g8f6  3. g1f3  3... b8d7 An interesting and modern idea, usually implemented by creative players. If White plays d4, Black sometimes goes with the knight to the strange square on b6. 4. e1g1  4... e7e5  5. d2d3 Can we call this a Pirc Defense with reversed colors or is that pushing the envelope $2 Regardless of how best to name this position, the computer is not very impressed with White's system. 5... c7c6 