NONE Role (mc)
The default role for all newly-created users on MC is NONE, which prevents users granted this role from configuring the MC. When you create MC users with the NONE role, you grant them an MC database-level role. This assignment maps the MC user to a user account on a specific database and specifies that the NONE user inherits the database user’s privileges to which he or she is mapped.
Which database-level role you grant this user with NONE privileges—whether ADMIN (db) or IT (db) or USER (db)—depends on the level of access you want the user to have on the MC-managed database. Database roles have no impact on the ADMIN and IT roles at the MC configuration level.