Property groups that were introduced in a given version of a module are marked with a \since command. This typically reports that a QML property was introduced in a version of that module, even if it is part of a property group. See, for example, the targetProperty group of QtQuick.Behavior:
https://doc-snapshots.qt.io/qt6-dev/qml-qtquick-behavior.html#targetProperty-prop

In cases like these, the documentation should mention the "property group" instead of a "QML property".