QWebEnginePage url property is missing NOTIFY. While it has the urlChanged signal, it is missing from the Q_PROPERTY declaration.

This makes this class not usable from QML. Whenever you try to bind to this property

Control {
    property var page: SomeAttachedProperty.page
    property url url: page.url 
}

you get error in logs:

QQmlExpression: ...
depends on non-NOTIFYable properties:
QWebEnginePage::url

QWebEnginePage class has urlChanged dignal, but is is not declared as NOTIFY for url property:

class Q_WEBENGINECORE_EXPORT QWebEnginePage : public QObject
{
    ...
    Q_PROPERTY(QUrl url READ url WRITE setUrl)
    ...
Q_SIGNALS:
    ...
    void urlChanged(const QUrl &url);
    ...
}