caffeine software package provides prevent the desktop becoming idle in full-screen mode, 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 caffeine
caffeine is installed in your system.
Make ensure the caffeine package were installed using the commands given below,
$ sudo dpkg-query -l | grep caffeine *
You will get with caffeine package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Miscellaneous |
| Package | caffeine |
| Version | 2.8.3-3build1 |
| Description | prevent the desktop becoming idle in full-screen mode |
| Sub Section | Misc |