I know that this is a bit off-topic here, but I guess that people reading this list could also be interested in the following question: Where are - if at all - go server protocols discussed/specified? Any pointers are welcome.
The protocol used by IGS and NNGS is not discussed publicly because IGS takes the position that the protocols are protected by copyright and that NNGS is in violation of their copyright. Legally, their position is absurd (and I got an opinion from FSF counsel Eben Moglin affirming this). But IGS has succeeded in stiffling discussion of the protocol.
Nils Lohner and Adriaan van Kessel undertook a project of rewritting the NNGS server code. They had some idea of converting the protocols to XML. But they didn't get very far with the protocol revision. Also, as far as I know no server uses their code. Now Nils is in graduate school and this project seems to have stopped.
Dan