Rated 5 out of 5 stars

le Wirek ar Aib. 20, 2016 ·

I see no difference between this and other very similar plug-in (PHP Manual Search 20080924 by Blueⓘ) except THIS ONE is newer, 3 times smaller (e.g. without trashy reference to "http://kr.search.yahoo.com/" in the XML plug-in file) and is better described with a better (more telling) screenshot.
It would be even better if it was showing search suggestions for those with poor memory. ;-)