This is just another indicator for Lock Keys with fancy icons which can enable and disable Caps Lock and Num Lock directly from the Graphical User Interface.
Use the following ppa (only Ubuntu >= 15.04 is supported):
sudo add-apt-repository ppa:l3on/indicator-lockkeys
sudo apt-get update
sudo apt-get install indicator-lockkeys
Then exec indicator-lockkeys from command-line or logout and login
in Unity again.
Install the deps:
sudo apt-get install valac libgtk-3-dev libappindicator3-dev libcaribou-dev libgtk-3-bin
Build and install system wide:
make
sudo make install