Explanation:

The Salesforce B2B Commerce object that needs to have a record added when defining a new Subscriber Page to be rendered in a CC Page is CC Subscriber Pages. This is a custom object that stores information about the Subscriber Pages, such as the name, description, URL, and Visualforce page. To create a new Subscriber Page, the user needs to create a new record in this object and specify the required fields. The user can then select the Subscriber Page from the CC Page Settings configuration in CCAdmin.

Salesforce References: B2B Commerce and D2C Commerce Developer Guide, Subscriber Pages