/usr/share/doc/linux-lowlatency-lts-xenial/changelog.gz is in linux-lowlatency-lts-xenial 4.4.0.21.22.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/linux-lowlatency-lts-xenial/../linux-image-lowlatency/changelog.gz