8/1B6/p7/1p1p4/2p2n2/P1P1k3/1KP5/8 b - - 0 1
Yes, Kd2 is a hard move to find here- it seems logical to simply play a5 as Yifan did, but that is likely only a draw in the end after white closes off the d2 square with 2.Kc1.
1...Kd2!!! 2. Bxa6 Nd3+!!
a) 3. cxd3 d4!!, 5. dxc4 (5. cxd4 c3+! -+) dxc3+ and Black wins
b) 3. Kb1 Ne1!, 4. Bxb5 Nxc2, 5. Bc6 Ne3, 6. a4 Kxc3, 7. a5 Kd2!, 8. a6 c3, 9. Ba4 Nc4, 10. a7 Nb6, 11. Ka2 c2, 12. Bxc2 Kxc2, 13 Ka3 Kc3! (keeping White King at bay), 14. Ka2 d4, 15. Kb1 d3, 16. Kc1 d2+, 17. Kd1 Na8 and Black wins
It's a winning position for black.
I think she should have played Kd2.