/etc/ is in network-manager 1.6.2-3+deb9u2.
This file is owned by root:root, with mode 0o755.
..
/etc/NetworkManager/
/etc/NetworkManager/NetworkManager.conf
/etc/NetworkManager/VPN/
/etc/NetworkManager/conf.d/
/etc/NetworkManager/dispatcher.d/
/etc/NetworkManager/dispatcher.d/01ifupdown
/etc/NetworkManager/dispatcher.d/no-wait.d/
/etc/NetworkManager/dispatcher.d/pre-down.d/
/etc/NetworkManager/dispatcher.d/pre-up.d/
/etc/NetworkManager/dnsmasq-shared.d/
/etc/NetworkManager/dnsmasq.d/
/etc/NetworkManager/system-connections/
/etc/dbus-1/
/etc/dbus-1/system.d/
/etc/dbus-1/system.d/nm-dispatcher.conf
/etc/dbus-1/system.d/org.freedesktop.NetworkManager.conf
/etc/init.d/
/etc/init.d/network-manager