/usr/share/doc/linux-tools-3.13.0-57-generic/changelog.Debian.gz is in linux-tools-3.13.0-57-generic 3.13.0-57.95.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/linux-tools-3.13.0-57-generic/../linux-tools-3.13.0-57/changelog.Debian.gz