This Datacron unlocks the codex entry - Galactic History 42: The Nevoota Extinction
This datacron holds unheard of power and knowledge collected by an ancient race. You access its power and discover writings which are clearly only one small piece of a massive galactic history:
Some years before the Old Sith Wars, the Nevoota--a species of insectoid aliens from the Balmorra system--found themselves facing an army of disciplined warriors in distinctive armor. The warriors were Mandalorian Crusaders, testing themselves against the galaxy's deadliest species.
However, the Nevoota were a challenge even for the Mandalorians. Possessing superior numbers and utterly disdainful of death, the Nevoota fought a four-year campaign under the cunning warlord Ithcharaka--but finally the Mandalorians hunted the Nevoota to extinction.
This conflict had a profound effect on Mandalorian culture. The Mandalorians began to see war itself as an end, not just a means of conquest. Through war, Mandalorian society found its highest expression. When Mandalore the Indomitable eventually rose to power, he led a people who demanded nothing less than the greatest challenges the galaxy could offer.
Coordinates X 2075 , Y 461
To reach this Datacron you need to jump down onto a large rock in southern Tatooine and kill your way through a tunnel infested with Sand People. The rock you need to jump down to is located near 2073 , 441 (Screenshots 1 & 2). Take your time getting down to it and heal up when you make it down there because you'll be at low health. If you're higher level you won't even need to kill any of the Sand People, at level 50 I just ran right through. Or if you have stealth you can just use that.
At the very end of the tunnel you'll find the Datacron hanging out on the rock ledge.