The pawn sacrifice transformed into an exchange sacrifice.  The permanently weakened white king, and especially the weak light squares around it, promise Firouzja a long-lasting initiative. An important detail is that both players started to think on their own immediately after the  novelty.
1. e2e4  1... c7c6  2. d2d4  2... d7d5  3. e4e5  3... c8f5  4. g1f3  4... e7e6  5. f1e2  5... g8e7  6. c2c3  6... e7g6  7. e1g1  7... b8d7  8. f3e1 Probably the most important maneuver in the  Advance Caro-Kann. White is ready to bring his pawns into motion. 8... h7h5  9. c1e3  9... d8b6  10. b2b3  10... f7f6 A sharp novelty by the young prodigy.  Black sacrifices a pawn but destroys the enemy center. 11. e2h5 Principled. 11... f6e5  12. g2g4 Sharp and risky play by Tari  in return. 12... h8h5 The only move. 13. g4h5 