The feeder cable type is not verified. It does not appear to be NM cable, but it could possibly be hard or extra-hard usage type cable. I have also been told the hard or extra-hard cables are designed for physical abuse, but trying to find any supporting documentation what type of abuse is acceptable that will not cause physical damage is not readily available.
The NEC & OSHA is very vague on this issue. It would be helpful with more examples of acceptable uses for cords and cables used for branch circuits and feeders for temporary wiring.