The Cairn Installation was a substantial asteroid base connected to the Empire Reborn. It resided inside the Cairn asteroid, which itself was situated within the Lenico Belt.
The base, constructed within the solid rock of the stable asteroid, accommodated the cortosis-processing operations of Galak Fyyar's forces, notably his shadowtroopers. The factory also produced a large number of dropships, loaded with stormtroopers and AT-STs, which Fyyar intended to deploy against the Jedi Praxeum located on Yavin 4.
In 12 ABY, Kyle Katarn and Luke Skywalker infiltrated the facility while searching for Desann. Katarn navigated through the hangars and the massive reactor core, confronting various Reborn Dark Jedi. Subsequently, Katarn successfully boarded the Doomgiver as it departed, sabotaging its systems while it was traveling towards its designated target.
Two missions that featured the Cairn Installation from Jedi Knight II were removed from the game's final release: cairn_docks2 and cairn_stockpile. Evidence of these missions can be found within the game's files. The term "cairn" originates from Scottish Gaelic and refers to man-made piles of stones found in the real world.