404. That’s an error.

The requested URL /custom?q=%22prefix+key%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=AELymgXSujqHMN6-1HVzcKAqz7n1kkztfhKFHPgdza6dmaH4IfDUWL0iI2nBySvfPof8jCnJ3Fhnvxgab5aE8W9y8gItfstjnjlaDjm7Ga5Dp6wr3qJiTw0&hl=en&boostcse=0&ie=UTF-8&oe=UTF-8&prmd=ivns&ei=p622VuyHFsOWmwGR56iYDA&start=80&sa=N was not found on this server. That’s all we know.