Index: wp-includes/feed.php
===================================================================
--- wp-includes/feed.php	(revision 26671)
+++ wp-includes/feed.php	(working copy)
@@ -27,6 +27,14 @@
  */
 function get_bloginfo_rss($show = '') {
 	$info = strip_tags(get_bloginfo($show));
+	/**
+	 * Filter the bloginfo for use in feeds.
+	 *
+	 * @since 2.2.0
+	 *
+	 * @param string $string Converted string value of the blog information.
+	 * @param string $show   Optional keyword naming the blog information you want.
+	 */
 	return apply_filters('get_bloginfo_rss', convert_chars($info), $show);
 }
 
@@ -46,6 +54,14 @@
  * @param string $show See get_bloginfo() for possible values.
  */
 function bloginfo_rss($show = '') {
+	/**
+	 * Filter the RSS container for the bloginfo for use in feeds.
+	 *
+	 * @since 2.1.0
+	 *
+	 * @param string $string RSS container for the blog information.
+	 * @param string $show   Optional keyword naming the blog information you want.
+	 */
 	echo apply_filters('bloginfo_rss', get_bloginfo_rss($show), $show);
 }
 
@@ -63,6 +79,13 @@
  * @return string Default feed, or for example 'rss2', 'atom', etc.
  */
 function get_default_feed() {
+	/**
+	 * Filter the default feed type.
+	 *
+	 * @since 2.5.0
+	 *
+	 * @param string $feed_type Default feed type, for example 'rss2', 'atom', etc.
+	 */
 	$default_feed = apply_filters('default_feed', 'rss2');
 	return 'rss' == $default_feed ? 'rss2' : $default_feed;
 }
@@ -83,6 +106,14 @@
 	$title = wp_title($sep, false);
 	if ( is_wp_error( $title ) )
 		return $title->get_error_message();
+	/**
+	 * Filter the blog title for the feed title.
+	 *
+	 * @since 2.2.0
+	 *
+	 * @param string $title The current post title returned by wp_title().
+	 * @param string $sep   Optional separator.
+	 */
 	$title = apply_filters( 'get_wp_title_rss', $title, $sep );
 	return $title;
 }
@@ -99,6 +130,14 @@
  * @param string $sep Optional.
  */
 function wp_title_rss( $sep = '»' ) {
+	/**
+	 * Filter the the blog title for display of the feed title.
+	 *
+	 * @since 2.2.0
+	 *
+	 * @param string $string The current post title returned by get_wp_title_rss().
+	 * @param string $sep    Optional separator.
+	 */
 	echo apply_filters( 'wp_title_rss', get_wp_title_rss( $sep ), $sep );
 }
 
@@ -114,6 +153,13 @@
  */
 function get_the_title_rss() {
 	$title = get_the_title();
+	/**
+	 * Filter the post title for the feed.
+	 *
+	 * @since 1.2.1
+	 *
+	 * @param string $title The current post title returned by get_the_title().
+	 */
 	$title = apply_filters('the_title_rss', $title);
 	return $title;
 }
@@ -146,8 +192,17 @@
 	if ( !$feed_type )
 		$feed_type = get_default_feed();
 
+	/** This filter is documented in wp-admin/post-template.php */
 	$content = apply_filters('the_content', get_the_content());
 	$content = str_replace(']]>', ']]>', $content);
+	/**
+	 * Filter the post content for use in feeds.
+	 *
+	 * @since 2.9.0
+	 *
+	 * @param string $content   The current post content.
+	 * @param string $feed_type Feed type returned by get_default_feed(), for example 'rss2', 'atom', etc.
+	 */
 	return apply_filters('the_content_feed', $content, $feed_type);
 }
 
@@ -176,6 +231,13 @@
  */
 function the_excerpt_rss() {
 	$output = get_the_excerpt();
+	/**
+	 * Filter the post excerpt for the feed.
+	 *
+	 * @since 1.2.1
+	 *
+	 * @param string $output The current post excerpt returned by get_the_excerpt().
+	 */
 	echo apply_filters('the_excerpt_rss', $output);
 }
 
@@ -188,6 +250,13 @@
  * @uses apply_filters() Call 'the_permalink_rss' on the post permalink
  */
 function the_permalink_rss() {
+	/**
+	 * Filter the permalink to the post for use in feeds.
+	 *
+	 * @since 2.3.0
+	 *
+	 * @param string $string The current post permalink.
+	 */
 	echo esc_url( apply_filters('the_permalink_rss', get_permalink() ));
 }
 
@@ -198,6 +267,13 @@
  * @return none
  */
 function comments_link_feed() {
+	/**
+	 * Filter the permalink to the comments for the current post.
+	 *
+	 * @since 3.6.0
+	 *
+	 * @param string $string The current comment permalink with '#comments' appended.
+	 */
 	echo esc_url( apply_filters( 'comments_link_feed', get_comments_link() ) );
 }
 
@@ -239,6 +315,13 @@
  * @since 1.5.0
  */
 function comment_link() {
+	/**
+	 * Filter the permalink to the given comment.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param string $string The current comment permalink returned by get_comment_link().
+	 */
 	echo esc_url( apply_filters( 'comment_link', get_comment_link() ) );
 }
 
@@ -254,6 +337,13 @@
  * @return string Comment Author
  */
 function get_comment_author_rss() {
+	/**
+	 * Filter the current comment author for use in the feeds.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param string $string The current comment author returned by get_comment_author().
+	 */
 	return apply_filters('comment_author_rss', get_comment_author() );
 }
 
@@ -279,6 +369,13 @@
  */
 function comment_text_rss() {
 	$comment_text = get_comment_text();
+	/**
+	 * Filter the current comment content for use in feeds.
+	 *
+	 * @since 1.5.2
+	 *
+	 * @param string $comment_text The comment content returned by get_comment_text().
+	 */
 	$comment_text = apply_filters('comment_text_rss', $comment_text);
 	echo $comment_text;
 }
@@ -329,6 +426,14 @@
 			$the_list .= "\t\t<category><![CDATA[" . @html_entity_decode( $cat_name, ENT_COMPAT, get_option('blog_charset') ) . "]]></category>\n";
 	}
 
+	/**
+	 * Filter all of the post categories for displaying in the feed.
+	 *
+	 * @since 2.2.0
+	 *
+	 * @param string $the_list All of the post categories for displaying in the feed.
+	 * @param string $type     Feed type returned by get_default_feed(), for example 'rss2', 'atom', etc.
+	 */
 	return apply_filters('the_category_rss', $the_list, $type);
 }
 
@@ -395,6 +500,13 @@
 				$t = preg_split('/[ \t]/', trim($enclosure[2]) );
 				$type = $t[0];
 
+				/**
+				 * Filter the RSS enclosure HTML enclosure tag for the current post.
+				 *
+				 * @since 2.2.0
+				 *
+				 * @param string $string The link HTML tag with a URI and other attributes.
+				 */
 				echo apply_filters('rss_enclosure', '<enclosure url="' . trim(htmlspecialchars($enclosure[0])) . '" length="' . trim($enclosure[1]) . '" type="' . $type . '" />' . "\n");
 			}
 		}
@@ -426,6 +538,13 @@
 		if ($key == 'enclosure') {
 			foreach ( (array) $val as $enc ) {
 				$enclosure = explode("\n", $enc);
+				/**
+				 * Filter the atom enclosure HTML link tag for the current post.
+				 *
+				 * @since 2.2.0
+				 *
+				 * @param string $string The link HTML tag with a URI and other attributes.
+				 */
 				echo apply_filters('atom_enclosure', '<link href="' . trim(htmlspecialchars($enclosure[0])) . '" rel="enclosure" length="' . trim($enclosure[1]) . '" type="' . trim($enclosure[2]) . '" />' . "\n");
 			}
 		}
@@ -488,6 +607,13 @@
  */
 function self_link() {
 	$host = @parse_url(home_url());
+	/**
+	 * Filter the feed URL.
+	 *
+	 * @since 3.6.0
+	 *
+	 * @param string $string The link for the feed with set scheme.
+	 */
 	echo esc_url( apply_filters( 'self_link', set_url_scheme( 'http://' . $host['host'] . wp_unslash( $_SERVER['REQUEST_URI'] ) ) ) );
 }
 
@@ -512,6 +638,14 @@
 
 	$content_type = ( !empty($types[$type]) ) ? $types[$type] : 'application/octet-stream';
 
+	/**
+	 * Filter the feed content type.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param string $content_type Media type indicating the type of data that a feed contains.
+	 * @param string $type         Feed type returned by get_default_feed(), for example 'rss2', 'atom', etc.
+	 */
 	return apply_filters( 'feed_content_type', $content_type, $type );
 }
 
@@ -541,6 +675,14 @@
 
 	$feed->set_feed_url( $url );
 	$feed->set_cache_duration( apply_filters( 'wp_feed_cache_transient_lifetime', 12 * HOUR_IN_SECONDS, $url ) );
+	/**
+	 * Fires just before processing the SimplePie feed object.
+	 *
+	 * @since 3.0.0
+	 *
+	 * @param object &$feed SimplePie feed object, passed by reference.
+	 * @param mixed  $url   URL of feed to retrieve. If an array of URLs, the feeds are merged.
+	 */
 	do_action_ref_array( 'wp_feed_options', array( &$feed, $url ) );
 	$feed->init();
 	$feed->handle_content_type();