Symptoms:
For the master database, you can find various configurations such as backup storage redundancy configured locally or geographically.
Since this is a non-configurable property, you might wonder why your database is configured with this value.
solve:
For the master database in Azure SQL Database Server, Microsoft manages this database as part of the server entity.
There are also other properties that cannot be configured on the customer side, as the SLO level of the master database (which can be system or system2) cannot be changed.
The master database is part of the server entity and should not store user data. Therefore, its only purpose is to operate server objects.
Backup Redundancy is displayed as one of the properties displayed for the database object, but is not related to the master database.
In any case, Microsoft implements mechanisms to maintain high availability of this database and security of the database server.