How to search documentation/manual?

Sorry if I missed this, but is there a way to search the online documentation/manual? I don’t see a way to search when I go to this link:
http://xibo.org.uk/manual/en/index.html

There’s no built in search function. It’s categorised into sections so it’s easy to navigate.

If you want to search it, you can do so using Google and restricting the search to the manual URL - by using the Advanced Search function.