How will backup be performed for a database that is used for several WordPress instances?
For example, there is only 1 database in Domains > example.com > Databases and it is used for two WordPress instances for the same domain. Will it be backed up only once or two times when creating a backup for a subscription?
Since there is only 1 database under the subscription, it will be physically backed up only once. Database and WordPress instance are different backup objects: WordPress instance does not contain the database, it only refers to one.