Install gir1.2-nmgtk-1.0 by entering the following commands in the terminal:
sudo apt update sudo apt install gir1.2-nmgtk-1.0
Description:
GObject introspection data for libnm-gtk
The libnm-gtk library provides Gtk+ dialogs for NetworkManager. . This package contains introspection data for libnm-gtk. . It can be used by packages using the GIRepository format to generate dynamic bindings.
Homepage: https://www.gnome.org/projects/NetworkManager/
Version: 1.8.10-2ubuntu1
Section: introspection