Given a QObject derived class defining a QFlag like this:

class TestObject : public QObject
{
    Q_OBJECT
    enum TestFlag {
      Value1 = 0x1,
      Value2 = 0x2
    }
    Q_DECLARE_FLAG(TestFlags, TestFlag)
    Q_FLAG(TestFlags)
}

When trying to retrieve the typename using QMetaObject the value has changed from Qt 5.13 to Qt6:

QMetaType::typeName(QMetaTypeId<TestObject::TestFlags>());

With 5.13 this returns: TestObject::TestFlags
Qt 6 returns: QFlags<TestObject::TestFlag>