Of unknown origin, the vessel was involved in smuggling starship components from the depot by taking the place of the holding vessel USS Tripoli. This combat vessel's armaments were considerable – its phasers were powerful enough to reduce a Galaxy-class starship's shields by at least 15% in a single volley.
Following the discovery of the remains of the Vulcan vessel T'Pau's navigational deflector, the USS Enterprise-D uncovered the operation, and - disguised as an abandoned ship - lay in wait for the vessel's arrival. When it took position to receive that day's shipment of goods, the Enterprise powered up and attempted to make contact. The vessel responded to hails by opening fire. A low-power phaser burst in return destroyed one of its phaser arrays, and caused collateral damage in her cargo bays - which at the time were fully loaded, mostly with weaponry. This led to massive power fluctuations and internal explosions, finally resulting in the destruction of the entire ship. (TNG: "Unification I")
Deep Space 9 visitors
Qualor II surplus depot
The Qualor II Surplus Depot Z15 was a Federation junkyard that contained the hulks of numerous retired starships, along with at least two space stations. Among the identified vessels that were located at the depot were the Apollo-class T'Pau, located at Section 18-Alpha-12, and the holding vessel USS Tripoli, located along the outer rim.
Tyken's Rift being vessel
This alien vessel escaped from the Tyken's Rift in 2367 following a collaboration with the Enterprise-D. Both ships were trapped in the Tyken's Rift. It was a glowing vessel belonging to an alien being. (TNG: "Night Terrors")
Vessels on file in LCARS
In 2364, Lieutenant Commander Data viewed three classes of ships in his search of the files in the USS Enterprise-D library computer. It was not known for whom these classes operated for or represented. The general assumption was that these classes of ships were operational in the mid-24th century.
The toxic waste barge was a large, unoccupied sublight freighter carrying toxic waste that had been drifting through space, eventually endangering the population of Gamelan V in 2367. Upon receiving distress calls from the planet, the USS Enterprise-D towed the barge into the Gamelan sun, almost getting lethal doses of radiation in the process. The barge's propulsion system employed a gaseous core fission reactor but it appeared to have been inactive 300 years. Geordi La Forge referred to it as a "garbage scow." (TNG: "Final Mission")