USB 3.1 require a different front panel header than USB 3.0.
The USB 3.1 port interface is using the USB 3.0 pin set and more. It is design to be backwards compatible
There are no official release of the specs for the USB 3.1 header yet
But first motherboard with this is the ASUS ROG MAXIMUS IX FORMULA, STRIX Z270I/Z270G etc.
Length: 30cm
Connector1: USB 3.0 Front Panel Header
Connector2: USB 3.1 Front Panel Header