/usr/share/doc/librack-ruby/changelog.Debian.gz is in librack-ruby 1.5.2-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/librack-ruby/../ruby-rack/changelog.Debian.gz
/usr/share/doc/librack-ruby/../ruby-rack/changelog.Debian.gz