With this feature, the Accesstype team has introduced "Custom Fields" which allows users to capture metadata such as Name, Phone Number, Email Address, and Address in the Subscription Group details page in AT dashboard.
Earlier it used to be only "Add New Field" which has now been elaborated as Custom Fields which can be customized by a publisher and can be filled by the user on the website.

Screenshot of the Custom Fields Now and Then:
 

You can also refer Types of subscription groups and How to create a subscription group here.