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=AELymgWThOsSbitYvOWmz--uizQCx_w8E47EVtQkATq2Jox8B_DixrRxusXtflx19z9rD4YN2ztbk1D79-K9nzSmXwNMV4ETzVv4gc8EBYrDsCdj5joo-HQ&hl=en&boostcse=0&ie=UTF-8&oe=UTF-8&prmd=ivnsp&ei=IRiGWND_Nqqu0gLqiY3oBw&start=30&sa=N was not found on this server. That’s all we know.