/usr/share/doc/libpresage1-dbg/changelog.Debian.gz is in libpresage1-dbg 0.9.1-2.1ubuntu4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libpresage1-dbg/../libpresage1v5/changelog.Debian.gz