The clandestine Trasse Proving Grounds on Trasse served as an Imperial manufacturing hub where All Terrain Armored Transports were built. A component of the production involved outdoor live-fire testing of the AT-ATs, utilizing prisoners as targets within two distinct ranges: one designed for infantry, and another for armored vehicles.
Following his choice to join the Rebel Alliance, Brenn Tantor leveraged information provided by Beri Tulon, a fellow defector who had previously been assigned to the grounds, to execute a raid with the goal of capturing an AT-AT walker.