WordPress/wp-includes/feed-rss2-comments.php

<?php
header('Content-Type: text/xml;charset=' . get_option('blog_charset'), true);

echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>'; 
?>
<!-- generator="wordpress/<?php echo $wp_version ?>" -->
<rss version="2.0" 
	xmlns:content="http://purl.org/rss/1.0/modules/content/">
<channel>
	<title><?php
		if ( is_singular() )
			printf(__('Comments on: %s'), get_the_title_rss());
		elseif ( is_search() )
			printf(__('Comments for %s searching on %s'), get_bloginfo_rss( 'name' ), attribute_escape($wp_query->query_vars['s']));
		else
			printf(__('Comments for %s'), get_bloginfo_rss( 'name' ) . get_wp_title_rss());
	?></title>
	<link><?php (is_single()) ? permalink_single_rss() : bloginfo_rss("url") ?></link>
	<description><?php bloginfo_rss("description") ?></description>
	<pubDate><?php echo gmdate('r'); ?></pubDate>
	<generator>http://wordpress.org/?v=<?php echo $wp_version ?></generator>

<?php 
if ( have_comments() ) : while ( have_comments() ) : the_comment();
	$comment_post = get_post($comment->comment_post_ID);
	get_post_custom($comment_post->ID);
?>
	<item>
		<title><?php
			if ( !is_singular() ) {
				$title = get_the_title($comment_post->ID);
				$title = apply_filters('the_title', $title);
				$title = apply_filters('the_title_rss', $title);
				printf(__('Comment on %1$s by %2$s'), $title, get_comment_author_rss());
			} else {
				printf(__('By: %s'), get_comment_author_rss());
			}
		?></title>
		<link><?php comment_link() ?></link>
		<author><?php echo get_comment_author_rss() ?></author>
		<pubDate><?php echo mysql2date('D, d M Y H:i:s +0000', get_comment_time('Y-m-d H:i:s', true), false); ?></pubDate>
		<guid><?php comment_link() ?></guid>
<?php if (!empty($comment_post->post_password) && $_COOKIE['wp-postpass'] != $comment_post->post_password) : ?>
		<description><?php _e('Protected Comments: Please enter your password to view comments.'); ?></description>
		<content:encoded><![CDATA[<?php echo get_the_password_form() ?>]]></content:encoded>
<?php else : // post pass ?>
		<description><?php comment_text_rss() ?></description>
		<content:encoded><![CDATA[<?php comment_text() ?>]]></content:encoded>
<?php endif; // post pass
	do_action('commentrss2_item', $comment->comment_ID, $comment_post->ID);
?>
	</item>
<?php endwhile; endif; ?>
</channel>
</rss>