gnome-shell-extension-caffeine software package provides GNOME Shell extension to keep your computer awake, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install gnome-shell-extension-caffeine
gnome-shell-extension-caffeine is installed in your system.
Make ensure the gnome-shell-extension-caffeine package were installed using the commands given below,
$ sudo dpkg-query -l | grep gnome-shell-extension-caffeine*
You will get with gnome-shell-extension-caffeine package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | GNOME |
| Package | gnome-shell-extension-caffeine |
| Version | 0~git20160329-3 |
| Description | GNOME Shell extension to keep your computer awake |
| Sub Section | gnome |