Youtube: Nadia Heninger - 48ce563f89a0ed9414f5aa28ad0d96d6795f9c62

As outlined in the video, the string "8ce563f89a0ed9414f5aa28ad0d96d6795f9c6" is common to the x coordinate of G*inv2 of all secp-k1 curves. I think it is very likely that 48ce563f89a0ed9414f5aa28ad0d96d6795f9c62 (with perhaps the first and last character (4 bits) changed) was/is generated by hashing some input, and then that was used as the basis for arriving at G.

It would be interesting to know what the original input to the hash function was, and the rationale behind the changed/added bits.