Ground beef got a C which tells me everything I need to know about the utility of the system.
And wow, what a bunch of poppycock that nutriscore that system is. I'd heard of it but never looked into it. It considers "high" saturated fat, or "high" salt, or "high" energy density as negatives.
If the scale is A-F, that would put ground beef at about average which seems about right. Its a great source of protein and a good source of some vitamins and minerals, but is high in saturated fat and has a low amount of other vitamins and minerals.