CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
and therefore can be supported by more hardware. Technically ECM and
EEM are designed for different applications. The ECM model extends
the network interface to the target (e.g. a USB cable modem), and the
EEM model is for mobile devices to communicate with hosts using
ethernet over USB. For Linux gadgets, however, the interface with
the host is the same (a usbX device), so the differences are minimal.

If you say "y" here, the Ethernet gadget driver will use the EEM
protocol rather than ECM. If unsure, say "n".