But given the shape, there isn’t much internal room, and that’s my point. Consider how they’ve put conformal tanks on the later F16s.
The YF-23 is a pretty and sleek plane, but there isn’t much volume to it.
I think you’d be surprised. The trapezoidal wings of the YF-23 have a LOT of internal volume dedicated to fuel, and there were big side saddle tanks outboard of the engines. Plus the aircraft’s weapons bay was long but shallow. The “hump” behind the cockpit was mostly a big fuel tank too.
The production F-23 was going to be larger than the YF-23 as well.