Jusqu'en USB 3.0, les choses étaient encore simples à saisir, puis est venu l'USB 3.1 et la nomenclature en a pris un coup :

" With USB 3.1 the bandwidth doubled to 10 Gbit/s. But USB-IF called it "USB 3.1 Gen 2" with the "old" USB 3.0 to be refereed to as "USB 3.1 Gen1". They did it again in 2017 with what people would have liked to be "USB 3.2". We got 20 Gbit/s except it was to be called "USB 3.2 Gen 2x2". Accordingly "USB 3.1 Gen 2" became "USB 3.2 Gen 2x1" and "USB 3.1 Gen 1" was renamed "USB 3.2 Gen 1x1"."

Sans compter la possibilité de transmettre un signal Display Port, le Power Delivery (USB-PD), etc.

Voir aussi la cheatsheet que l'auteur a publié : https://fabiensanglard.net/usbcheat/index.html