The Vorknkx Project was an Imperial project carried out before the Battle of Endor to create low-power cloaking devices for freighters. Results of the project were stored at Mount Tantiss, and were collected by Thrawn in 9 ABY.
The ultimate goal was to use this technology to cloak Imperial starfighters. The testbed for the project was a Corellian corvette called the Vorknkx, hence the project's name. The project was so secret that only Emperor Palpatine, head of new technology Grand Admiral Demetrius Zaarin, and the project's staff knew anything of its existence.
After Zaarin's coup on the Emperor failed, he set his sights on damaging Imperial manufacturing capabilities and gaining technological advantages. Shortly after a failed attempt to capture prototype Missile Boats, Zaarin took his forces into hiding. He later reemerged and sent a modified frigate, Z-Borus, to capture the space station laboratory of the Vorknkx Project. Grand Admiral Thrawn, who had been tasked by the Emperor to capture or kill Zaarin, sent his best pilot, Maarek Stele, in a Missile Boat to defend the base; the modified frigate Z-Borus was destroyed, and the project was relocated to an abandoned mine on an asteroid called To-phalion Base.
However, Zaarin had planted spies in the facility, and they succeeded in stealing the corvette Vorknkx. What Zaarin didn't know was that Thrawn had anticipated this move and planted a tracking device on the ship. Thrawn's task force followed and trapped Zaarin at the very edge of the Outer Rim, where he planned to regroup his forces. Zaarin was forced to abandon his Star Destroyer, Glory, during the fight, and he and some of his officers fled on the Vorknkx. To mask their escape while entering hyperspace, they activated its cloaking device. Unknown to them, the Vorknkx Project scientists had earlier discovered that the device would overload, and probably explode, if used in conjunction with hyperspace engines. Their ignorance of this was due to Thrawn having had this information erased from the project logs. As a result, Zaarin and all on board the Vorknkx perished in an explosion.
The Vorknkx Project was cut afterward, as its testbed and only working prototype was destroyed, and the subsequent death of the Emperor prohibited any revival of the project. To Thrawn the project served only one purpose, the destruction of Zaarin.