Documentation in the source code follows doxygen style (http://www.stack.nl/~dimitri/doxygen/docblocks.html#pythonblocks). You can generate the doxygen docs by running make doxygen in the doc directory. The resulting HTML is stored in doc/doxygen/html.
This docbook documentation can be generated by running make docbook in the doc directory. The resulting HTML is stored in doc/html.
With plain make both documentation types will be generated.