To help with man-db development, you'll probably want to start by checking out the latest code from revision control:
git clone git://git.sv.gnu.org/man-db.git
Or, if your firewall prevents you using the git protocol:
git clone http://git.savannah.gnu.org/r/man-db.git
./autogen.sh before starting. You'll need
Gettext; it is usually
best to install your distribution's packages of these if available. You
may also want to have a copy of
You should read the docs/HACKING file.
You can also just browse the source code using a web browser.
There is a mailing list for developers, although it is as yet rather quiet.