| XBC | Use X-Midas primitives inside NeXtMidas. |
| NeXtOpt | Use NeXtMidas as an X-Midas option tree. |
| XBC | Used when a NeXtMidas application needs to use an existing X-Midas primitive. |
| NeXtOpt | Used when an X-Midas application needs to use NeXtMidas functionality. |