Question about G4MaterialPropertiesTable (OpNovice extended example)

I understand that optical properties of a material are stored in the G4MaterialPropertiesTable, but I am not sure what the below values are (from extended example OpNovice, or how they obtained:

From the units, I would guess this is penetration depth. Could someone kindly confirm?

It’s the absorption length. See here:

I would not take the values in the examples to be anything more than representative examples. In your application, best to look up values.