The moniker Arbiter was a fabrication of Yrica Quell's mind, a New Republic pilot infiltrating the Galactic Empire's 204th Imperial Fighter Wing as a mole, when she struggled to recall the name of Colonel Madrighast's _Imperial_-class Star Destroyer, the [Unyielding] (/article/unyielding), during the events of 5 ABY.
Alexander Freed included the Arbiter in his 2021 novel, Victory's Price: An Alphabet Squadron Novel, which served as the concluding chapter in the Star Wars: Alphabet Squadron trilogy.