Go to the URL of your site and add “/wp-admin” to the end. For example, if your site is www.example.com, you would go to www.example.com/wp-admin. If you get a login page it is a wordpress site. If it is then there are wordpress plugins that do full backups.
Ok, I tried that (adding the “/wp-admin”) and got a “forbidden access” error message.
So I guess that confirms it’s not a wordpress site.