The user can resize and rotate the Shape named "SHAPE" in the Nodes. In addition to the normal features of the RotatingTool, the SpotRotatingTool shows a handle at the Part.rotationSpot, which is also at the RotatingTool.rotationPoint. The user can drag that handle and thereby move the rotationPoint and the Part.rotationSpot. When the handle is inside the rectangular area of the Part.rotateObject, the Spot is purely fractional. When the handle moves outside of the object's rectangular area, the spot will be at the edge of the rectangle plus an offset.
This extension tool is defined in its own file, as SpotRotatingTool.js.