The master branch only contains licensing, readme and binaries -- if you need access to release source code then these bundles are at:

https://github.com/unserializable/monchester/releases/

And if you more specifically are looking to work with code, then look at:

https://github.com/unserializable/monchester/branches

• Windows binaries for version 1.0 provided by Günther Simon of RWBC (https://rwbc-chess.de/)