us-url-mailto 1) ("^[^:]+:" "11(<11(url: 11)711 (nntpllinews11):11([^>In ]*11)>I1)" 1 (>= gnus-button-message-level 0) gnus-button-message-id 4)) "*Alist of headers and regexps to match buttons in article heads. This alist is very similar to 'gnus-button-alist', except that each alist has an additiona