.JBK File Extension
What is a JBK file?
Backup file created by Juno Internet service software; introduced with version 5 of the Juno software and contains backups of program files and user data such as email; saved in a proprietary format and used for restoring data with the Juno software.
NOTE: You need a Juno account to download the Juno Software. JBK backups are specific to each account.