300.4(G)
Insulated Fittings. Where raceways contain 4 AWG or larger insulated circuit conductors, and these conductors
enter a cabinet, a box, an enclosure, or a raceway, the conductors shall be protected by an identified fitting providing a smoothly rounded insulating surface, unless the conductors are separated from the fitting or raceway by identified insulating material that is securely fastened in place.
They could be listed if they're not intended to put conductors #4 or larger in the conduit.
