Ethernet max speed

The only device for USB Ethernet on your website is rated at USB2.
Can somebody please tell me if USB3 is not available for Ethernet as that would be a problem for me.
I really want to buy this but Ethernet and lack of Linux is stopping me.
WIFI ac sucks:-(

@plasta-blasta Have you checked out this new Mezzanine board, now available through Arrow Electronics

It was announced last year, but only recently hit the shelves.