Merge commits '4494a369 3aef6ab8 0fa84f86 249c81ea 7966aee3 fb758fe8 3fc1de5c 0aacf643 9e6d1b0e 332af315 afd7eb4a c9ebca95 cc557575 0f7657d5 907a6721 b40e2d30 c545fdc3 2bd5f3e6 0e00fc7d c734c642 26392da2 ' into temp-merge-1386

src/group.h

@@ -112,7 +112,8 @@ static void secp256k1_gej_set_ge(secp256k1_gej *r, const secp256k1_ge *a);
 /** Check two group elements (jacobian) for equality in variable time. */
 static int secp256k1_gej_eq_var(const secp256k1_gej *a, const secp256k1_gej *b);
 
-/** Compare the X coordinate of a group element (jacobian). */
+/** Compare the X coordinate of a group element (jacobian).
+  * The magnitude of the group element's X coordinate must not exceed 31. */
 static int secp256k1_gej_eq_x_var(const secp256k1_fe *x, const secp256k1_gej *a);
 
 /** Set r equal to the inverse of a (i.e., mirrored around the X axis) */