Voss Presence Datacron Location
This Datacron unlocks the codex entry - Galactic History 75: The Jedi Civil War
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:
Revan and Malak, once great Jedi, had turned to the dark side and sought to conquer the Republic. With an infinite fleet produced by the Star Forge space station, they seemed as unstoppable as the Mandalorians. They took control of entire systems and established a new Sith academy on Korriban.
This time, the Jedi Council did not hesitate to act. The Republic lured the Sith Lords into battle against a small fleet. This allowed a Jedi strike team led by Bastila Shan to board Darth Revan's flagship.
Darth Malak had plans of his own. Having grudgingly taken his role as Revan's apprentice, he decided to usurp his master. With the Jedi providing a perfect distraction, Malak fired on Revan's flagship, destroying the bridge. Malak claimed the title of Dark Lord, not realizing the Jedi strike team had survived and taken Revan--injured, but alive--as their prisoner.
How To Retrieve This Datacron
This Datacron as well as Cunning +4 are both located in The Nightmare Lands, so you will want to get both of these back to back. The location of this Datacron is far northeast in The Nightmare Lands, you will need to access to Spirit World in order to retrieve this Datacron which can only be accessed through the Meditation Tablet (Screenshots 1 & 2). The Datacron is in the middle of the room which you're taken too after using the tablet. To get back out to the real world use the tablet again near where you came in.
Location on the map of the Meditation tablet.