This file comes to your browser with a 200 status code (All OK), but it is an error page 404 (client requested a non existent resource). But to send you a 404 status code may cause your browser to to show a generic error message and not this one and as you can see this page does exist, but only to tell you that it does not exist.
For past pages that may have existed at sometime try this and for future pages that may never exist try here ...