indicators-client software package provides Indicators client test application, 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 indicators-client
indicators-client is installed in your system.
Make ensure the indicators-client package were installed using the commands given below,
$ sudo dpkg-query -l | grep indicators-client *
You will get with indicators-client package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | X Window System software |
| Package | indicators-client |
| Version | 8.12+16.04.20160401-0ubuntu1 |
| Description | Indicators client test application |
| Sub Section | X318 |