Oh I meant "nope" to your comment that you can't name any board that as a USB 3.1 gen 2 connector for the front panel, which I could and found very confusing 😛 Should have made that clear. The issue I had and where I had to read the manual (which I only do AFTER I get the motherboard) to find out wether it was a USB-C header or not.
But basically I think that if a mobo says "Front USB 3.1 Gen 2" it will mean a USB-C header right? Even though gen 2 doesn't mean it's Type C, and a type C connection won't mean it's gen 2.
As to your last alinea, I just looked up the B450 Tomahawk as you recommend it often and I think I get what you mean. When speaking about USB 3.1 (gen 2) it does refer to the USB-C connection at the back of the motherboard, not about a header.