fact: Definition plus_hfiber_to_plus {X Y : Type} (f : X -> Y) (y : Y) : plus_hfiber f y o to_plus L O (hfiber f y) == functor_hfiber (fun u => (to_plus_natural L O f u)^) y.
imports: HoTT.Basics HoTT.Types Extensions HFiber Truncations NullHomotopy Limits.Pullback Descent Lex Separated