/usr/share/doc/libdisplaymigration0-dbg/changelog.Debian.gz is in libdisplaymigration0-dbg 0.28-11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libdisplaymigration0-dbg/../libdisplaymigration0/changelog.Debian.gz