/usr/share/doc/libharfbuzz0b-dbg/changelog.Debian.gz is in libharfbuzz0b-dbg 1.0.1-1ubuntu0.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libharfbuzz0b-dbg/../libharfbuzz0b/changelog.Debian.gz