Is there documentation on File/New/Package?

In the File menu there is an opportunity to open a file as a package using File/New/Package. That opens a specialized GUI with the option to run and debug code. When we look up documentation on this here is what we get:

Does anyone know the whereabouts of some useful documentation, or even a tutorial giving the intended use of this capability and an example?

Kind regards,
David

Take a look at this and this.