When you create a backup file, either from the menu selection or by scheduling a backup, QuickBooks saves the most recent copy of more than just your company file.
If information were saved to these files, they were included in the backup. The actual files in your backup shows in the QBBackup.log file.
Find and open the QBBackup.log file:
Use the QBBackup.log file to see which files are included and then find their file size in Windows.