$ sudo apt-get update
$ sudo apt-get install libindicator3-tools 

libindicator3-tools is installed in your system.

Make ensure the libindicator3-tools package were installed using the commands given below,

$ sudo dpkg-query -l | grep libindicator3-tools *

You will get with libindicator3-tools package name, version, architecture and description in a table

libindicator3-tools package basic information: