There is no official documentation for this desired functionality to customize/add to the Catalog.
Information as to how this could / would be handled depending on how you plan to manage this scenario.
The suggestion is to properly build a set of Signatures and a Product that has
“No License Required”
In this way can you can report on it but there will not be reporting on the Compliance,
And this way you do not need a License or an Article..
If you for some reason want it in the Compliance report then you need to put a Metric on the Product
and build an Article and a “fake” license to achieve license balance.