What is the "Restore file share permissions" option?
Google Drive files and folders can be shared among multiple users. When you restore files from your own Drive, checking the “Restore file share permissions” option ensures that all shared files will be restored with its original permission settings.
Restore files with its original permissions
When the option is enabled, share permissions to edit, comment, or view the files will be restored to the same users and groups as the original backup. Please note that if files are being restored to an account that is not the original owner, that user will become the new owner of the files.
If the option is left unchecked, all permissions on the restored file will be reset so that it is only accessible to the target account. You can manually reset the permissions in Google Drive later.