How to use a virtual interface in Qml with qmlRegisterInterface?

[c64zottel]

The documentation is kind of sparse in this area: http://doc.qt.io/qt-5/qqmlengine.html#qmlRegisterInterface

I tried to register my Interface like this:

qmlRegisterInterface<InputDeviceConfigurator>( "InputDeviceConfigurator" );

But I can not import it because there is no version number and just using it out of the blue gives the "is not a type" error.

If I declare the type as follows:

qmlRegisterUncreatableType<InputDeviceConfigurator>(
            "InputDeviceConfigurator", 1, 0, "InputDeviceConfigurator", "Not creatable in Qml." );

It works just fine.

So, what do I not understand with qmlRegisterInterface?