/usr/share/doc/gir1.2-dbusmenu-gtk3-0.4/changelog.Debian.gz is in gir1.2-dbusmenu-gtk3-0.4 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/gir1.2-dbusmenu-gtk3-0.4/../libdbusmenu-glib4/changelog.Debian.gz