Welcome to the KGDB wiki, the official home of kgdb for kernel.org.
KGDB Mailing list
The git branch is organized into the pieces that are not in the main line kernel. The top level link to the development git archive is here:
There is a branch head for each kernel release starting with 2.6.21. Starting in 2.6.24 the kgdb internals were completely changed. The kgdb core was merged to the mainline kernel in 2.6.26.
There is also a directory with a quilt series corresponding to the kgdb development git archive which is periodically updated. It can be found at: http://kernel.org/pub/linux/kernel/people/jwessel/branches
KGDB kernel documentation
Linux Plumbers Conference presentation 2009
This presentation used kdb_prototype8 from the kgdb git repository. This was an intermediate build of the 2.6.32 development kernel however while the KMS core was in flux, so it is not terribly useful to anyone except as a demonstration.
The kdb_prototype9 branch was created after the KMS core changes stabilized and will form the basis for the cleanup and initial post to lkml.