@Eelco, in the line:

...e5 2.Nde2 b5 3.g4 b4 4.Nd5 Nxd5 5.Qxd5 Ra7 6.Be3 Be6 7.Qd2 Rd7 8.Qxb4 d5 9.Qa4 Be7 10.c3 Bg5 11.O-O-O Bxe3+ 12.fxe3 O-O 13.Bg2 dxe4 14.Qxe4 Qa5

White has much stronger Ng3 instead of g4. And now it's problem for Black, cause this horsy can jump into f5. There are games with Ng3 Qc7 but no equality there.

I would not combine ...e5 and ...b5 myself. But that is what Stockfish wants to play. I don't know about Nf5 after Ng3 though. Maybe? In this wild line White indeed got an edge. This is with Contempt negative, -5

Engine: Stock Dev 20190504 (512 MB)

by T. Romstad, M. Costalba, J. Kiiski, G. Linscott

38 42:51 +0.77 10...Be6 11.Nxf6+ gxf6 12.Qf3 Qc5

13.O-O-O Rg8 14.Rhe1 a5 15.Kb1 Qc6

16.Be3 Rd8 17.Bb6 Rxg2 18.Ka1 Rd6

19.Qxg2 Nxb6 20.Qg3 Bxb3 21.cxb3 Nd7

22.Nc1 Qc2 23.Rxd6 Bxd6 (3.957.416.177) 1538

38 42:51 +0.84 10...Qc7 11.O-O Be6 12.Re1 Nxh5

13.Qxh5 Bd6 14.Bxd5 Bxd5 15.Bxb4 O-O

16.Bxd6 Qxd6 17.Nc3 Be6 18.Rad1 Qc7

19.Qxe5 Qxe5 20.Rxe5 Rxb2 21.Rd2 g6

22.Nd1 Ra2 23.Ra5 Rc8 (3.957.416.177) 1538

38 42:51 +0.99 10...Rb7 11.Qf3 e4 12.Qe2 Be6 13.Rd1 Rd7

14.O-O Nxh5 15.Qxh5 Bc5 16.Be3 O-O

17.Bxc5 Qxc5 18.Qe5 Rc8 19.Bxd5 Bxd5

20.c3 bxc3 21.Nxc3 Rcd8 22.Rfe1 f6

23.Qf5 h6 (3.957.416.177) 1538

37 42:51 +1.22 10...e4 11.Qe2 Be6 12.O-O Nxh5

13.Qxh5 Be7 14.Rfe1 Qd8 15.Qe2 O-O

16.Rad1 Rb6 17.Qxe4 Rd6 18.Qf3 Rd7

19.Nc1 a5 20.Nd3 Bd6 21.Bc1 Nc7

22.Nf4 Bxb3 23.cxb3 Bc5 (3.957.416.177) 1538

37 42:51 +1.38 10...h6 11.O-O Be6 12.Re1 Nxh5

13.Qxh5 Bd6 14.Rxe5 Bxe5 15.Qxe5 O-O

16.Nxb4 Qc7 17.Qd4 Rxb4 18.Bxb4 Nxb4

19.Qxb4 Bxb3 20.cxb3 Rb8 21.Qc4 Qxc4

22.bxc4 Rxb2 23.Rc1 Kf8 (3.957.416.177) 1538

This was also with Contempt -5 Only very short PV after ...e5 I did not wait for depth 50 there.

Engine: Stock Dev (512 MB)

by T. Romstad, M. Costalba, J. Kiiski, G. Linscott

50 1148:50 +0.13 1...b5 2.g4 Bb7 3.Bg2 Nc6 4.Nxc6 Bxc6

5.g5 Nd7 6.Be3 e6 7.Qd4 a5 8.a3 e5

9.Qd2 Be7 10.O-O Rb8 11.b3 Nc5

12.Rad1 O-O 13.Rfe1 b4 14.axb4 Rxb4 (101.438.752.275) 1471

50 1148:50 +0.21 1...h6 2.g4 e6 3.a3 b5 4.Bg2 Bb7

5.f4 Nbd7 6.Qe2 Rc8 7.Bd2 Be7

8.O-O-O Qb6 9.Nb3 Nc5 10.Nxc5 Qxc5

11.Kb1 Qc4 12.Rhe1 Qxe2 13.Rxe2 Nd7

14.Na2 O-O (101.438.752.275) 1471

49 1148:50 +0.13 1...e5 2.Nde2 (101.438.752.275) 1471

49 1148:50 +0.18 1...Nc6 2.g4 g6 3.Be3 Nxd4 4.Bxd4 Bh6

5.Nd5 O-O 6.Bxf6 exf6 7.Qd4 Bg7

8.Qb6 f5 9.Qxd8 Rxd8 10.exf5 Bxb2

11.Rb1 Ba3 12.Bg2 gxf5 13.Kd2 Ra7

14.Ne7+ Kf8 (101.438.752.275) 1471