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=AELymgWdWCtOqQmFNm3Esr46aVF3t5I5sfudP5jizHvupBTXc_0wmmXxjP2_DrZ_5-5CBivaFo_QDPp9h5Uol2n7oQTuNQAtFP5wJq582EQ7w_kXsS9uNac&hl=en&boostcse=0&ie=UTF-8&oe=UTF-8&prmd=ivns&ei=6p1WVqufIcnteuiehtgI&start=50&sa=N was not found on this server. That’s all we know.