/usr/share/doc/linux-tools-4.8.0-56-generic/changelog.Debian.gz is in linux-tools-4.8.0-56-generic 4.8.0-56.61~16.04.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/linux-tools-4.8.0-56-generic/../linux-hwe-tools-4.8.0-56/changelog.Debian.gz