com.unity.perception/com.unity.perception/Editor/Randomization/ParameterDragBar.cs

using UnityEngine.UIElements;

namespace UnityEngine.Experimental.Perception.Randomization.Editor
{
    class ParameterDragBar : VisualElement
    {
        public ParameterDragBar()
        {
            AddToClassList("parameter-drag-bar");
        }
    }
}