HTML Canvas Add Managed Child use

I saw this line of code in my exports and was wondering what it does. I traced it back to the MovieClip class using it to addManagedChild. Does anyone know what is the advantage of addManagedChild over the regular addChild?

this.timeline.addTween(cjs.Tween.get({}).to({state:[{t:this.shape_2},{t:this.shape_1},{t:this.shape}]}).wait(1));