gnome-shell-extensions software package provides Extensions to extend functionality of GNOME Shell, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gnome-shell-extensions
gnome-shell-extensions is installed in your system.
Make ensure the gnome-shell-extensions package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnome-shell-extensions *
You will get with gnome-shell-extensions package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | GNOME |
| Package | gnome-shell-extensions |
| Version | 3.14.2-1 |
| Description | Extensions to extend functionality of GNOME Shell |
| Sub Section | GNOME |