The EF78 Nebulon-B2 Heavy Frigate, sometimes known just as Rebel Heavy Frigate or Modified Frigate, was a design developed by the Alliance to Restore the Republic in an effort to fix the weaknesses of the regular EF76 Nebulon-B Escort Frigate. This comes about after the loss of the former Alliance Fleet Flagship the EF76 Nebulon-B Frigate Salvation at the Battle of the Itani Nebula and various reports of other notable losses of Escort Frigates in both Alliance and Imperial Fleet.