QML extension plugin is unusable if registerTypes() doesn't register any types

If no types are registered to the given uri in QQmlExtensionPlugin::registerTypes(), QML cannot import the plugin. Error message:

module "MyModule" is not installed

This prevents one from creating a plugin that places data to the root context of an engine only.

Work-around:

qmlRegisterType<QObject>(uri, 1, 0, "__QTBUG_WORKAROUND__");