This Datacron unlocks the codex entry - Galactic History 78: The Sith Triumvirate
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:
In the chaos after the Jedi Civil War, new Sith began to rise up, inspired by the likes of Exar Kun and Darth Revan and unaware of the Sith Empire still hidden on Dromund Kaas. Three lords stood above all others: Darth Nihilus, whose hunger devoured all life around him; Darth Sion, whose shattered body was held together by hatred; and Darth Traya, once a Jedi Master but now the Lord of Betrayal. These Sith Lords ruled from ancient Sith ruins on Malachor Five.
Darth Traya was the most senior of the three, but when Sion and Nihilus united against her, she fled Malachor Five and took the name Kreia. Darth Sion created an elite cadre of Sith assassins, eroding the already-weakened Jedi from the shadows, while Darth Nihilus began roaming the galaxy, seeking the life energy of Force users to satisfy his insatiable hunger. The Republic's short reprieve was over.
This Datacron is located the southeastern portion of the Government District. The small metal beam you need to climb up ontop of is at 3118 , -1843 (Screenshots 1 & 2). From this steel beam you need to jump to a slender iron beam that slowly moves up and down the large rock pillar directly in front of you (Screenshot 3). At the top of this iron beam run off of it onto the large stone column. You'll be able to see the Datacron in the distance now, but how do we get there?!?!?!
Position yourself between the bomb at the top of this column and the Datacron in the distance, like I am in (Screenshot 4). Right click the bomb and BOOM you will be airborn and flying to the Datacron. You will faceplant the ground like I am in (Screenshot 5), just jump to get up and then grab the Datacron.