If you click on that link, the positions are described, although it is not defined which codes mean what. You can check individual public fares on experflyer to figure out it for yourself (14 days free trial) or maybe someone has a link to a document, I don't.

NDC gives airlines a lot more options to decouple things that are in old-school GDS coupled to a given fare class. For example, a true full-range dynamic pricing, not just selecting from preexisting options. It also makes it a lot easier to offer ancillary services and mix and match offers as needed. But from a pax perspective, there is very little difference usually.

Booking class as we talk about it here (i.e. "the letter") is RBD. I'm not sure if AF uses "dual RBD" which gives like a secondary discrimination in the second leter in other classes, but not in longhaul J. There it is either R or G for direction, but I am not sure what the direction is. But, for CDG-SIN, G is inbound, for CDG-GRU, G is outbound, so....