Plesk for Linux stores backup files in compressed GZIP archives. Only the server administrator with access to server shell can unpack these archives.
To unpack a backup file:
/usr/local/psa/bin/backup-unpack extract <path to backup file>, where <path to backup file> is commonly
/var/lib/psa/dumps/<client ID>/<domain ID>/<backup file name>.
The utility will create the directory
/var/lib/psa/dumps/<client ID>/<domain ID>/ and will place all content there.