In the Connected servers dialog area, specific information is displayed for each server in the Type and Role columns.
You will find a detailed explanation of this below:
The type [Type] is defined in the license file:
The MASTER/BACKUP role [Role] indicates which server is currently the authoritative server.
(There is always a server with the MASTER role.)
If the master fails, the backup server takes over, but it can only run for a limited period of time.
As soon as the master is back, it is immediately assigned the "Backup" role again.
The longest running server becomes the master as long as 2 other nodes in the cluster are online. (The cluster has quorum.)
There is no limit to the backup time (because in a 3-node cluster there is actually no server with the specific orientation "Always Master").