private static DataFlavor createLocalTreeNodeFlavor() {
        try {
            return new GenericDataFlavor(
                DataFlavor.javaJVMLocalObjectMimeType+
                "; class=java.util.ArrayList", 
                "Local list of Drag/Drop Tree objects");
        }catch (Exception e) {
            Msg.showError(DragDropTreeTransferable.class, null, null, null, e);
        }
        return null;
    }
A static instance of the local tree node flavor that is an
ArrayList of DragDropNode objects.
Ghidra/Framework/Docking/src/main/java/docking/dnd/DragDropTreeTransferable.java