This is a positive side of the active placement of the bishop. It is normally safer  on f1, but can never show activity from there. Nakamura also frees the  road for his b-pawn.
1. e2e4  1... c7c5  2. g1f3  2... d7d6  3. f1b5  3... b8d7 A clear indicator that Black wants to keep as many pieces on the board and is ready for risky play. 4. b5a4  4... g8f6  5. e1g1  5... a7a6  6. c2c4  6... e7e6  7. b1c3  7... f8e7  8. d2d4  8... c5d4  9. f3d4 It all  transposed into a Hedgehog setup with a slightly weird-placed  light-squared white bishop. 9... e8g8  10. d1e2  10... d8c7  11. a4b3 More or less  necessary prophylaxis. 11... b7b6  12. c1e3 An obvious development and a novelty. 12... c8b7  13. f2f3  13... a8c8 Carlsen consistently prepares the Hedgehog d6-d5  and b6-b5 breaks in return. 14. a1c1  14... f8e8  15. f1d1  15... c7b8 