QUL does not currently have support for numbered arguments for strings in QML.
In Qt this is supported: https://doc.qt.io/qt-5/qml-qtqml-string.html#arg-method
This feature would be important for some cases regarding internationalization as in some languages the order of arguments may need to change, and this could be easily achieved by changing the order of the % arguments if those would be supported. In a similar manner like described at:
With current API this may be difficult to achieve sometimes, as languages tend to have different word order.