We could not find that page

The address you requested does not match anything on this synthetic fixture site, yet the server answered it with HTTP 200 anyway — the shape this corpus calls a soft-404.

The page is fully rendered on the server: an agent reading the response sees a heading, prose, a navigation list and a search prompt, and nothing in the status line or the markup says the requested route is missing. Every link below points at a page that does exist, which is exactly why a crawler will happily cache this response as if it were content.