Thread:Project:Support desk/Invalid url gets redirected to a different wiki folder/reply

MediaWiki doesn't redirect to the search when user request a page that doesn't exist. It seems to be a custom rewrite condition made on the web server.

In fact, accessing the link you provided, the first response is an HTTP 302 (redirect), which includes the HTTP header, and when the next page is reached, then the HTTP header changes to  , so the PHP engine isn't touched on the first redirect, confirming it's done by a rewrite rule on the web server.