The lack of an icon on the downloaded backup files is not an indication of the files being compromised. The backup files are in a .wpress format, which is specific to the All-in-One WP Migration plugin, and it’s likely that your operating system does not have a default application to associate with this file format, hence no icon is displayed.
If you want to verify the integrity of the backup files, you can use a tool like Traktor, which supports the .wpress format. You can check the validity of your backup files by either using the Traktor desktop application available at https://traktor.wp-migration.com or by dragging and dropping your backup file into the online tool at https://traktor.servmask.com
This should give you peace of mind regarding the status of your backup files.
