/usr/share/doc/librdf-ruby/changelog.Debian.gz is in librdf-ruby 1.0.17.1+dfsg-1.3build4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/librdf-ruby/../ruby-librdf/changelog.Debian.gz
/usr/share/doc/librdf-ruby/../ruby-librdf/changelog.Debian.gz