Kitsune is a very simple blogging software, it is written in less than 200 lines of code. It does support CSS and RSS.
Kitsune releases are available at http://download.gnu.org.ua/pub/release/kitsune.
For features like bug tracker see Kitsune project page at Puszcza.
You can check-out latest Kitsune source code from CVS using following command:
cvs -z3 -d :pserver:firstname.lastname@example.org:/cvsroot/kitsune co kitsune.
Kitsune is licensed under terms of MIT license (see license.txt in Kitsune distribution).
My name is Tomasz Konojacki. My home site address is http://www.xenu.cc.