This is just another indicator for Lock Keys with fancy icons which can enable and disable Caps Lock directly from the Graphical User Interface.
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
Then exec indicator-lockkeys
from command-line or logout and login
in Unity again.