/usr/share/doc/xserver-xorg-core-lts-trusty-dbg/changelog.Debian.gz is in xserver-xorg-core-lts-trusty-dbg 2:1.15.1-0ubuntu2~precise5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/xserver-xorg-core-lts-trusty-dbg/../xserver-xorg-core-lts-trusty/changelog.Debian.gz