WordPress Hooks

category_feed_link is a filter on the internal links generated for each category's feed.

Context:

File: wp-includes/feed-functions.php
function get_category_rss_link($echo = false, $cat_ID, $category_nicename) {
       $permalink_structure = get_settings('permalink_structure');

       if ('' == $permalink_structure) {
				 $link = get_settings('home') . '?feed=rss2&cat=' . $cat_ID;
       } else {
				 $link = get_category_link($cat_ID);
				 $link = $link . "feed/";
       }

			 $link = apply_filters('category_feed_link', $link);

       if ($echo) echo $link;
       return $link;
}

This hook is a filter which means that information is passed through it, and then used by WordPress. Your function needs to accept that information, and return it. Using add_filter('category_feed_link', 'your_function'); helps you to remember this distinction. When you are passing an ID, it is assumed that you will return the ID as it was given to you. With filters that pass strings or arrays, you may manipulate the information before passing it along.

This hook is filed under Categories, Feeds, Filter, Internal Links.