Index: feed-rss.php
===================================================================
--- feed-rss.php	(revision 11354)
+++ feed-rss.php	(working copy)
@@ -5,7 +5,7 @@
  * @package WordPress
  */
 
-header('Content-Type: ' . feed_content_type('rss') . '; charset=' . get_option('blog_charset'), true);
+header('Content-Type: ' . feed_content_type('rss-http') . '; charset=' . get_option('blog_charset'), true);
 $more = 1;
 
 echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>'; ?>
Index: feed-rss2-comments.php
===================================================================
--- feed-rss2-comments.php	(revision 11354)
+++ feed-rss2-comments.php	(working copy)
@@ -5,7 +5,7 @@
  * @package WordPress
  */
 
-header('Content-Type: ' . feed_content_type('rss2') . '; charset=' . get_option('blog_charset'), true);
+header('Content-Type: ' . feed_content_type('rss-http') . '; charset=' . get_option('blog_charset'), true);
 
 echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';
 ?>
Index: feed-rss2.php
===================================================================
--- feed-rss2.php	(revision 11354)
+++ feed-rss2.php	(working copy)
@@ -5,7 +5,7 @@
  * @package WordPress
  */
 
-header('Content-Type: ' . feed_content_type('rss2') . '; charset=' . get_option('blog_charset'), true);
+header('Content-Type: ' . feed_content_type('rss-http') . '; charset=' . get_option('blog_charset'), true);
 $more = 1;
 
 echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>'; ?>
Index: feed.php
===================================================================
--- feed.php	(revision 11354)
+++ feed.php	(working copy)
@@ -523,10 +523,11 @@
 		$type = get_default_feed();
 
 	$types = array(
-		'rss'  => 'text/xml',
-		'rss2' => 'text/xml',
+		'rss'  => 'application/rss+xml',
+		'rss2' => 'application/rss+xml',
+		'rss-http'  => 'text/xml',
 		'atom' => 'application/atom+xml',
-		'rdf'  => 'application/rdf+xml',
+		'rdf'  => 'application/rdf+xml'
 	);
 
 	$content_type = ( !empty($types[$type]) ) ? $types[$type] : 'application/octet-stream';