If you're a PHP developer, you'll likely often need to open up php.net to find out the [the order of ;)] arguments for a function. Generally i just type, php.net/functionname, but if you want to save 4 more keystrokes you can easily add a quick search.

He's included a screenshot of the interface to add it as well as the location to give - a URL pointing to the search page on the php.net website that looks in the "quickref" category for a match.