The Debian Archive Software consisting of dak (Debian Archive Kit) for the archive and the buildd related parts wanna-build/sbuild.
dak is the collection of programs (scripts) used to maintain the Debian project archive. You need a running postgresql
http://lists.debian.org/debian-dak/
All the archive info managed by dak are stored in the ProjectB database, which is accessible by all DebianDevelopers on mirror.ftp-master.debian.org.
Logs of Dak activity are also available in /srv/ftp-master.debian.org/log/current there as well.
See also: HowToSetupADebianRepository, DakHowTo, ProjectB.
Design
Dak is part of a larger ecosystem of multiple pieces of software interacting to make the FTP archive works.
The above graphic is generated from a dot file in the package-cycle git repository and maintained by TheAnarcat.
See also the releases workflow.