$ sudo apt-get update
$ sudo apt-get install plasma-active-webbrowser 

plasma-active-webbrowser is installed in your system.

Make ensure the plasma-active-webbrowser package were installed using the commands given below,

$ sudo dpkg-query -l | grep plasma-active-webbrowser *

You will get with plasma-active-webbrowser package name, version, architecture and description in a table

plasma-active-webbrowser package basic information: