Thrawn receives information about the initiative. Prior to the Battle of Endor, the Imperial Military undertook a secret initiative known as the Vorknkx Project. The aim of this project was to develop low-powered cloaking devices intended for use on freighters belonging to the Galactic Empire. The results and data from this project were stored within Mount Tantiss, and Thrawn acquired them in 9 ABY.
The ultimate objective involved adapting this technology to cloak Imperial starfighters. The Corellian corvette named Vorknkx served as the primary test platform for this project, which is where the project derived its designation. The project's secrecy was so tightly maintained that only Emperor Palpatine, the head of new technology Grand Admiral Demetrius Zaarin, and the personnel directly involved in the project had any knowledge of its existence.
After Zaarin's attempted coup against the Emperor failed, he redirected his efforts towards undermining the Empire's manufacturing capabilities and acquiring technological advantages. Following a failed attempt to seize prototype Missile Boats, Zaarin retreated into hiding with his forces. He eventually resurfaced, dispatching a modified frigate, the Z-Borus, to capture the space station laboratory that housed the Vorknkx Project. Grand Admiral Thrawn, under orders from the Emperor to capture or eliminate Zaarin, deployed his top pilot, Maarek Stele, in a Missile Boat to defend the base. The Z-Borus was destroyed, and the project was subsequently relocated to an abandoned mine situated on an asteroid known as To-phalion Base.
However, Zaarin had successfully infiltrated the facility with spies, who managed to steal the corvette Vorknkx. Unbeknownst to Zaarin, Thrawn had foreseen this eventuality and had placed a tracking device on the ship. Thrawn's task force tracked the Vorknkx and cornered Zaarin at the edge of the Outer Rim, where he intended to regroup his forces. During the ensuing battle, Zaarin was compelled to abandon his Star Destroyer, the Glory, and he and several of his officers escaped aboard the Vorknkx. To conceal their departure as they entered hyperspace, they activated the cloaking device. What they didn't realize was that Vorknkx Project scientists had determined that using the device in conjunction with hyperspace engines would cause it to overload and likely explode. Thrawn had intentionally removed this critical information from the project logs. Consequently, Zaarin and everyone aboard the Vorknkx perished in a catastrophic explosion.
Following these events, the Vorknkx Project was terminated. Its testbed and only functional prototype had been destroyed, and with the Emperor's death, there was no possibility of reviving the project. For Thrawn, the project had served a single, crucial purpose: the elimination of Zaarin.