The B28 Extinction-class bomber, otherwise known as the B-28, represented a class of starfighter utilized by the revived Sith Empire during both the Great Galactic War and the subsequent Cold War.
This particular bomber was heavily involved in the Sacking of Coruscant, where squadrons of these ships inflicted widespread destruction upon the urban landscape of Coruscant. In the course of the Cold War, the Keizar-Volvec bulk cruiser named Paramount transported a number of B-28s, employing them to unleash a bombardment on the planet Sebaddon as part of Independent Operation Sebaddon in 3643 BBY.
At approximately this time, a working version of the bomber was in existence.