In Qt Quick / QML documentation, the code snippet on Behavior element page is wrong.

Now the snippet is:

Rectangle {
width: 20; height: 20
color: "#00ff00"
y: 200 //initial value
y: Behavior {
NumberAnimation

{ easing: "easeOutBounce(amplitude:100)" duration: 200 }

}
}

This would work:

Rectangle {
width: 20; height: 20
color: "#00ff00"
y: 200 //initial value
Behavior on y {
NumberAnimation

{ easing.type: Easing.OutBounce easing.amplitude: 100 duration: 200 }

}
}