+<item>
+ <tags>'ds' 'defsearch'</tags>
+ <spec>'defsearch' 'ds'</spec>
+ <type>&option.defsearch.type;</type>
+ <default>&option.defsearch.default;</default>
+ <description>
+ <p>
+ Sets the default search engine. The default search engine is
+ used by <ex>:open</ex> and related commands for arguments which
+ include no search or bookmark keywords and can't otherwise be
+ converted into URLs or existing file names.
+ </p>
+
+ <p>
+ This means that with <o>defsearch</o> set to <str>youtube</str>,
+ <ex>:open Tim Minchin</ex> behaves exactly as
+ <ex>:open youtube Tim Minchin</ex>, so long as you don't have a
+ search or bookmark keyword called ‘Tim’.
+ </p>
+ </description>
+</item>
+