Changing form handlers?

My apologies for not fully understanding the programmatic flow in Omeka S.
I want to send the results from the advanced search page to a different handler, but I can’t see how that form is tied to the default handler.

It currently calls the IndexController’s searchAction method, but I can’t see where that connection is made.

Can anyone point me in the right direction?

Self-answered (in case anyone else has the same issue). The Controller (in my case) was defined in the addRoutes method in Module.php