The NL bumper tube can only accommodate a 2-prong Valterra-brand female end, as opposed to the more common 4-prong female ends. Each new NL should come with a Valterra female fitting, which you are expected to mount to a hose.
Some of us have discovered that you can shave a standard 4-prong hose to fit. I posted my success story here: https://www.facebook.com/groups/1055863797841588/permalink/2299084473519508/
Whether a shaved 4-prong or as-is 2-prong, the female end will only fit near the opening of the bumper tube, so you can only mount one fully-fitted tube in the bumper.
Just today, rumor broke that the 2020 NL will have a bigger bumper box to accommodate the 4-prong sewer hoses.
--SiletzSpey