What is a backup file and how do I open a backup file?
BACKUP files are created by some Android mobile devices through the advanced startup mode when pressing and holding the power button and volume button, then choosing the option to backup user information. They are saved to the Android SD card when backup is complete. BACKUP files contain user information such as contacts and user files. They are useful for archiving save points from mobile devices so the data can be restored if there is a problem with the device.
Relevant backup file links:How to open backup file on Youtube
How to open backup file on Wikipedia
How to open backup file on Microsoft.com