This looks like what the Nebulon B should have been, however under the empire, the military contracts demanded mass over quality. I can see the hull's been reinforced. Perhaps the New Republic fielded this ship to replace its aging Nebulon B, and at the same time, field a much more capable patrol frigate against Imperial incursions. It looks like there's dual turbolasers along the spine, and streamlined energy conduits feeding through the spine to the engine block's reactors. Perhaps a design feature KDY never capitalized much upon. And it looks like KDY went all-out trying to upgrade the Nebulon B design in order to earn back contracts after building star destroyers for the empire, they decided to get the contracts they lost to the Sullust Shipyards and the Mon Calamari. Either way, it was good business for KDY to support the New Republic when the Empire began to loose.