Custom nodes are saved as a bbasset. So when you import the bbasset with the node, it will be part of an object. You can import the bbasset either by dragging it into the 3D World or clicking on the little plus sign in the 3D World located at the bottom of the 3D World object list and just to the left of the little trash can icon. After importing the bbasset, it will be on the bottom of the list of objects on the far left of the window. Double-click on the object to open it in the Node editor. You will see the node in here. You can use with the imported object, or select the node, copy, then open the object you want to use it in and paste. Double-click on the node to see the associated JavaScript.
