404. That’s an error.

The requested URL /custom?q=%22Extensible%22&client=google-coop-np&cof=FORID:13%3BAH:left%3BS:http://www.emacswiki.org/%3BCX:Emacs%2520Wiki%2520Search%3BL:http://www.emacswiki.org/emacs_rss.png%3BLH:43%3BLP:1%3BVLC:%23551a8b%3BDIV:%23cccccc%3B&cx=004774160799092323420:6-ff2s0o6yi&adkw=AELymgX8kp3FgRIFSK5vIzry6lNYNgoN6epBspicBXpyaY4lxr84qAuzB1H67AIfknU-gO1NpV--gQDl8b2WUHVV1HAOTsTFuj-SL5uvqyUuUS8GrNU7YA0&hl=en&boostcse=0&ie=UTF-8&oe=UTF-8&prmd=ivnsp&ei=NvpGWJqnF6aS6AT87ovYCQ&start=20&sa=N was not found on this server. That’s all we know.