Sorry, this chapter is still to be written... At the moment the source code is nearly completely documented with tags suitable with the KDE documentation tools. We currently prefer using doxygen. Maybe some day we will spend some time for writing a tool that converts the doxygen output into something we can include into the docbook source (the source this page has been built of).
If you want to write a plugin, contribute something to this project (or maybe write the converter mentioned above), please feel free to contact one of the authors directly and / or subscribe to the Kwave mailing list: "https://lists.sourceforge.net/lists/listinfo/kwave-devel". Help is always welcome!