Is it possible to add item properties to QML that will be inherited nested (of type Layout.*)?

Question

Qt

Good day!
In general, subject.
I want it like this:
MyItem.qml

Item {
   property Ext: { color: "black"; }
}

main.qml

MyItem {
   Rectangle {
      Ext.color: "silver"
   }
   Rectangle {
      Ext.color: "gold"
   }
}

I found in the documentation how to do this from C ++ by creating my own component.
But I can’t find it from pure QML or I’m not looking there at all.
Tell me, please, is it possible and how?

Answer 1

I don’t understand what is needed
either here
doc.qt.io/qt-5/qtqml-syntax-directoryimports.html
or
Image {
property bool checkable: true
source: "myFoto.img"
MouseArea {
anchors.fill: parent
onClicked: if(checkable === true) myFunction()
}
}