Before downloading the file, Plesk will prompt you to protect the backup with a password. Doing so encrypts the passwords stored in the Plesk database. This way, even if the backup file falls into the hands of a third party, they will not be able to obtain the passwords stored inside, as restoring a password-protecting file without providing the correct password results in all passwords being generated randomly. If you do not want to protect your backup with a password, clear the Use password protection checkbox.