Gall was a celestial body that possessed an Imperial spaceport. In 3 ABY, after the bounty hunter Boba Fett took the smuggler Han Solo into capture, Fett was spotted at the Gall spaceport getting his vessel, Slave I, fixed.
After finding out that Fett had been seen, Princess Leia Organa gathered a team of spacers to operate Solo's YT-1300 light freighter, the Millennium Falcon, so they could chase down the information and locate Solo.
Within the current Star Wars canon, Gall's initial mention occurred in the 2016 Friends Like These supplement for the Star Wars Roleplaying game by Fantasy Flight Games. The Star Wars Legends timeline is where Gall began as a moon, first appearing in X-Wing: Rogue Squadron, a novel authored by Michael A. Stackpole in 1996.