This is documentation for developers or for people who just want to hack on the code. It is not intended to replace the automatic API documentation generated by doxygen (we do have a doxyfile, right?), but is intended to supplement those documents with additional information that may not necessarily appear in the API docs. It is also not intended as a substitute for good commenting tactics. And finally, it is a place to put planning documentation (like the stuff Philippe writes), proposals, RFC-type material, and so forth. But not the roadmap, we use Sourceforge's tracker for that.