Using Database Backup Storage (Windows)
Starting from Plesk 12.5, we recommend that you use export and import operations to backup and restore databases. For details, see Exporting and Importing Database Dumps.
However, if you already have files in the database backup storage, then you can access them in Websites & Domains > Backup Manager > More Actions > Database Backup Repository. The only operations you can do on database backup files are downloading and removing.