deb-conffiles - package conffiles
conffiles
A package declares its list of conffiles by including a conffiles file in its control archive (i.e. DEBIAN/conffiles during package creation). This file contains a list of files, one per line. Trailing whitespace will be trimmed, and empty lines will be ignored.
/etc/alternatives/README /etc/cron.daily/dpkg /etc/dpkg/dpkg.cfg /etc/logrotate.d/dpkg
dpkg(1).