In particular XiStrat (abbreviation of 'eXtended, enhanced and eXtreme STRATegy') is about turn-based, networked multiplayer strategy board games (without chance) on 3D-visualized polyhedra.
By the help of a computer-provided 3D representation (look at it as an MVC (model-view-controller) design pattern) it is quite comfortable for humans to play on those boards.
Persistency is provided by a relational database (offering networked access) when actually creating or manipulating the 3D data, besides the XiStrat™ server uses the database for storing all relevant gaming data.
XML is / will be used for communicating information about the graphs and the available matches to clients. Besides thereby (using files instead of a database) you are able to handle the graphs directly (work offline so to say) and import them into other tools.