Loopback Interface

In the next release of RouterOS, it will be good to have a loopback interface.

You already can create loopback interface by adding bridge interface without bridge ports.

and that should be the loopback or just the bridge without any ports ? there is a difference.

As far as I know loopback interface is software interface to emulate physical interface. This is exactly what bridge without bridge ports does.
It is equivalent to cisco’s loopback interface.