Referentials

You can get the list of referential code list value by clicking on the button Code list values on the Attribute page : Attributes
If you want to do it via the API, you need to have an access token so you can list the referential code values.
The steps to get a token are described here: How to get your token

Once you are authenticated, you can list your referential code values.

API Reference

List referential code values