comment_author_rss
comment_author_rss is a filter on the output of the comment_author_rss() function, which echoes the name of the author of the current comment in the RSS feeds.
Context:
File: feed-functions.php
function comment_author_rss() {
$author = apply_filters('comment_author_rss', get_comment_author() );
echo $author;
}
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('comment_author_rss', '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.