/usr/share/doc/libdbusmenu-gtk-dev/changelog.Debian.gz is in libdbusmenu-gtk-dev 16.04.1+18.04.20171206-0ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libdbusmenu-gtk-dev/../gir1.2-dbusmenu-gtk-0.4/changelog.Debian.gz