XBoard Documentation Required (Chess)

Question

I am looking for XBoard documentation. XBoard is a communication protocol between chess and chess graphical interfaces.

I know about http://www.gnu.org/software/xboard/engine-intf.html , but it seems that the engine needs to send / receive to communicate with the board.

Something is better than advice on redesigning the protocol either from a GUI implementation (e.g. xchess or eboard) or using a chess engine. Even a board / engine comment can help.

Answer 1

From the comments:

Your link tells us that HGMuller is the current interface. His page shows the minimal interface you need to implement.