This Datacron unlocks the codex entry - Galactic History 80: A Return from Exile
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:
During the Mandalorian Wars, many Jedi disobeyed the Jedi Council to follow Revan's call to arms. But only one Jedi returned to face the Council's judgment. The so-called Jedi Exile had been one of Revan's generals, and she was responsible for the destruction of Malachor Five.
Having lost all ability to feel the Force, the Exile accepted the Council's sentence of banishment and left to wander the Outer Rim. When she returned years later, the Jedi had all but vanished--slain by mysterious Sith assassins or driven into hiding.
Simply by returning, the Exile became a target for these Sith and was hounded to the remote Peragus system. After meeting a mysterious Force-sensitive named Kreia at Peragus, the Exile began searching for any surviving Jedi Masters to discover what they knew.
This Datacron is located in the Government District of Corellia far in the northeastern section in the Republic Encampment of Port Pevaria (Screenshot 1). For Imperials getting this Datacron kinda sucks but for Republic it's easy as pie. What you need to do is enter Port Pevaria and head far northeast to where the zone ends and there is nothing but water below (Screenshot 2). Here you will see a set of brown pipes just off the edge of the catwalk that you need to jump down to (Screenshot 3).
Be careful not to hit your head when jumping to these pipes. If you want, it's actually easier to kinda squeeze under the platform above when you're standing on the railing and just drop down to the pipes. I fell a few times before figuring this out. Once you make it to the pipes head south underneath the catwalk. Helpful Tip: You can hug the wall without falling between the pipes and the wall.
Follow the pipes south until you reach where I am in (Screenshots 4 & 5). The Datacron is just ahead sitting on an invisible platform. From these Screenshots you will want to fall down onto the metal pipe I am looking at in (Screenshot 4) and run over to the Datacron. You can fall down right next to the Datacron here onto the invisible platform. To get out from here you'll need to either kill yourself or type /stuck.