QDS does not show all the properties when opening up, for example, Cluster_demo_2021. The properties "end" and "begin" are used for animating the demo, and are used in a timeline. However, they are not visible in the properties for setting key frames.
QML for ArcItem
    ArcItem {
        id: roundarcitem
        x: 627
        y: 207
        width: 666
        height: 663
        capStyle: 32
        strokeColor: "#09d7f6"
        fillColor: "#00000000"
        end: -158
        strokeWidth: 40
        begin: -158
    }

 Not Evaluated
  Not Evaluated                     
