Why a full subscription backup with a note Part of server backup is shown at Domains > example.com > Backup Manager?

Question

Why a full subscription backup with a note Part of server backup is shown at Domains > example.com > Backup Manager?

Answer

A server-wide backup that is created at Tools & Settings > Backup Manager includes subscription backups.

This server-wide backup appears in each subscription's backup list with a note Part of server backup (Created by the administrator from reseller's/customer's view) and contains data only of this particular subscription.