Step 5: Navigate to the folder you unzipped the Arduino IDE and go to the libraries folder.
...
you must copy all folders located in libraries folder of the lightsaber software ZIP file to this folder.
You should never install libraries to the Arduino IDE installation folder. The reason is they will all be lost whenever you update to a new version of the Arduino IDE. Instead, you should always install libraries to the sketchbook folder (reference: https://www.arduino.cc/en/guide/libraries#toc5).
From https://github.com/Protonerd/FX-SaberOS/wiki/Setting-up-Arduino:
You should never install libraries to the Arduino IDE installation folder. The reason is they will all be lost whenever you update to a new version of the Arduino IDE. Instead, you should always install libraries to the sketchbook folder (reference: https://www.arduino.cc/en/guide/libraries#toc5).