/usr/share/doc/libokular-ruby/changelog.Debian.gz is in libokular-ruby 4:4.13.0-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libokular-ruby/../ruby-kde4/changelog.Debian.gz
/usr/share/doc/libokular-ruby/../ruby-kde4/changelog.Debian.gz