Star Wars X-Wing (2nd Ed): Servants of Strife Squadron Pack - Rules of Play says:

Swarms of networked Vulture-class fighters commanded by tactical droids strike at innocent worlds, forcing the Republic on the defensive. All the while, Grievous slinks through the shadows in his customized Belbullab-22 Starfighter; hunting the Jedi at every turn. This Squadron Pack contains everything you need to add one Belbullab-22 Starfighter and two Vulture-class Droid Fighter ships to your games of X-Wing, including new ship and upgrade cards, three maneuver dials, and an array of tokens.