RhinoDoc.RuntimeSerialNumber property not persistent?

Hello all, I’m a little confused. The RhinoCommons API documentation says:

Unique serialNumber for the document while the application is running. This is not a persistent value.

Just to be clear, does this mean that for the same open document its serialNumber can change during runtime? Or more simply that a document previously saved to file might have a different serialNumber if opened again?

RhinoDoc.RuntimeSerialNumber Property

Thanks, Claudio

The latter. It will have a different value the next time.

Thanks Menno, your help is appreciated!