/usr/share/doc/gir1.2-networkmanager-1.0/changelog.Debian.gz is in gir1.2-networkmanager-1.0 1.2.6-0ubuntu0.16.04.3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/gir1.2-networkmanager-1.0/../libnm-util2/changelog.Debian.gz