deb-conffiles - package 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. They should be
listed as absolute pathnames, and should exist in the binary package,
otherwise dpkg(1) will ignore them (although by default
dpkg-deb(1) will refuse to build such binary packages). Trailing
whitespace will be trimmed, and empty lines will be ignored.