to add off what he said, its a firmware that is downloaded onto your memory cards. It is for most EOS series cameras. Look it up on youtube for tutorials to download. Its super safe and easy these days.
It is a firmware that opens up a lot of new features with your camera. Native ISO's, Zebras, AGC disable, waveform, Histogram, kelvin white balance, and many many more things. It is defiantly worth it to download. At first, you will be very confused with the way everything is lay'd out on your screen. Take your time to understand everything on it, then you will be good for the future.