Extending Default WordPress Search Functionality

Hi,

I am trying to extend the functionality of the WordPress search widget that is provided in wordpress/wp-includes/default-widgets.php. (The Class is WP_Widget_Search.) I am trying to trace the wires back and understand how the current widget works so I can extend its functionality, but one of the major things I do not understand is where the query placed in the search box is actually submitted to and where the posts are actually searched and selected for matching the search query.

By looking at the code so far, I see that when the query is submitted through the search box, the form action is ' . home_url( '/' ) . ' and I don’t really understand what that means or where it points. (I am assuming that this would be the file I’d want to be looking through to find the rest of the search functionality.)

Any help in resolving this question from people wiser and more learned in the ways of WordPress than myself would be greatly appreciated.

Thanks,
daniechiu