Developers are the last ones to write their own documentation and the first to complain when another hasn't done it. Fortunately for you, we have a smattering of some docs available for your reading pleasure.
The user's guide reads like a book. It has descriptive narratives and examples of using the individual parts of the Xyster Framework.
The API is automatically generated by phpDocumentor. It's a low-level specification detailing every last class and method. Very boring, we know, but extremely useful if you don't want to hunt around in the actual source code.