Debconf is a configuration management system for Debian packages.
Debconf is available in subversion at
is shipped as a package in the Debian distribution.
Though I implemented Debconf, I am not longer its main maintainer, it's now maintained by a team, and Colin Watson has been doing more work on it than me lately.
The eventual plan is to do away with the perl implementation of debconf, and switch Debian over to using cdebconf, which was developed as part of the debian-installer. While the first steps are aready being taken to running a system this way, there are a lot of packages whose dependencies make this hard to do. Bugs have been filed and bug #328498 is the tracking bug for this transition.