404 /-/-/-/-/-/-/-/-/-/-/

Every now and then I see a 404 for my website with the ip trying to access http://www.mywebsite.com/-/-/-/-/-/-/-/-/-/-/

do you know what the slashes are? At first I though it was because I have registration turned off and older registered pusher were trying to access s it.. but it happens after they visit the main index page also sometime not ljust if they are trying to log in

https://wordpress.org/plugins/wordfence/