It came directly off the Rendili StarDrive line for use on the project in 27 BBY. After Outbound Flight crashed on the Redoubt, Dreadnaught-Three was used as a place to exile Force-sensitives, due to its isolation. As of 22 ABY, that had only been done twice.
The ship was anomalous, in that it had no survivors after the crash, and contained a Delta-12 Skysprite, originally intended to carry Obi-Wan Kenobi and Anakin Skywalker back to the Republic before Outbound Flight left the galaxy. They were originally aboard under Mace Windu's orders to spy on Jorus C'baoth after his behavior became more and more erratic. They were eventually called off the ship at its last stop in Republic space by Supreme Chancellor Palpatine. Thus, the Skysprite was never utilized. Jorad Pressor's father disassembled the hyperdrive of the ship to prevent its Jedi captives from escaping.