gir1.2-mate-polkit software package provides GObject introspection data for mate-polkit, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gir1.2-mate-polkit
gir1.2-mate-polkit is installed in your system.
Make ensure the gir1.2-mate-polkit package were installed using the commands given below,
$ sudo dpkg-query -l | grep gir1.2-mate-polkit *
You will get with gir1.2-mate-polkit package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | X Window System software |
| Package | gir1.2-mate-polkit |
| Version | 1.12.0-3 |
| Description | GObject introspection data for mate-polkit |
| Sub Section | X218 |