A Digital Developer extends a system object, Product, andadds a Boolean attribute, “sellable,” to it.

When extending a system object in Salesforce B2C Commerce, such as adding a new attribute to the Product object, custom attributes are accessed through the custom namespace. Therefore, if a Boolean attribute named "sellable" is added to the Product object, it should be accessed as prod.custom.sellable. This approach is part of the platform's data customization framework, where custom provides a namespace for all user-defined extensions to system objects, ensuring that they do not conflict with existing system properties. Detailed usage and examples of accessing custom attributes can be found in the Salesforce Commerce Cloud Script API documentation under "System Object Types".