diff --git a/wp-includes/feed-atom-comments.php b/wp-includes/feed-atom-comments.php
index 13a55a206a..d9c8f6529d 100644
--- a/wp-includes/feed-atom-comments.php
+++ b/wp-includes/feed-atom-comments.php
@@ -7,15 +7,18 @@
 
 header('Content-Type: ' . feed_content_type('atom') . '; charset=' . get_option('blog_charset'), true);
 echo '<?xml version="1.0" encoding="' . get_option('blog_charset') . '" ?' . '>';
+
+/** This action is documented in wp-includes/feed-rss2.php */
+do_action( 'rss_tag_pre', 'atom-comments' );
 ?>
 <feed
 	xmlns="http://www.w3.org/2005/Atom"
 	xml:lang="<?php bloginfo_rss( 'language' ); ?>"
 	xmlns:thr="http://purl.org/syndication/thread/1.0"
-	<?php 
+	<?php
 		/** This action is documented in wp-includes/feed-atom.php */
-		do_action( 'atom_ns' ); 
-		
+		do_action( 'atom_ns' );
+
 		/**
 		 * Fires inside the feed tag in the Atom comment feed.
 		 *
@@ -49,7 +52,7 @@ echo '<?xml version="1.0" encoding="' . get_option('blog_charset') . '" ?' . '>'
 	<link rel="self" type="application/atom+xml" href="<?php bloginfo_rss('comments_atom_url'); ?>" />
 	<id><?php bloginfo_rss('comments_atom_url'); ?></id>
 <?php } ?>
-<?php 
+<?php
 	/**
 	 * Fires at the end of the Atom comment feed header.
 	 *
diff --git a/wp-includes/feed-atom.php b/wp-includes/feed-atom.php
index 666b52df99..ae4cd7976c 100644
--- a/wp-includes/feed-atom.php
+++ b/wp-includes/feed-atom.php
@@ -8,7 +8,11 @@
 header('Content-Type: ' . feed_content_type('atom') . '; charset=' . get_option('blog_charset'), true);
 $more = 1;
 
-echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>'; ?>
+echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';
+
+/** This action is documented in wp-includes/feed-rss2.php */
+do_action( 'rss_tag_pre', 'atom' );
+?>
 <feed
   xmlns="http://www.w3.org/2005/Atom"
   xmlns:thr="http://purl.org/syndication/thread/1.0"
diff --git a/wp-includes/feed-rdf.php b/wp-includes/feed-rdf.php
index d3503af40d..177ae96f6a 100644
--- a/wp-includes/feed-rdf.php
+++ b/wp-includes/feed-rdf.php
@@ -8,7 +8,11 @@
 header('Content-Type: ' . feed_content_type('rdf') . '; charset=' . get_option('blog_charset'), true);
 $more = 1;
 
-echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>'; ?>
+echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';
+
+/** This action is documented in wp-includes/feed-rss2.php */
+do_action( 'rss_tag_pre', 'rdf' );
+?>
 <rdf:RDF
 	xmlns="http://purl.org/rss/1.0/"
 	xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
diff --git a/wp-includes/feed-rss2-comments.php b/wp-includes/feed-rss2-comments.php
index a8a1c13bbe..2a71da1f2c 100644
--- a/wp-includes/feed-rss2-comments.php
+++ b/wp-includes/feed-rss2-comments.php
@@ -8,6 +8,9 @@
 header('Content-Type: ' . feed_content_type('rss-http') . '; charset=' . get_option('blog_charset'), true);
 
 echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';
+
+/** This action is documented in wp-includes/feed-rss2.php */
+do_action( 'rss_tag_pre', 'rss2-comments' );
 ?>
 <rss version="2.0"
 	xmlns:content="http://purl.org/rss/1.0/modules/content/"
diff --git a/wp-includes/feed-rss2.php b/wp-includes/feed-rss2.php
index 0ce4e6be51..f7da5f2a9a 100644
--- a/wp-includes/feed-rss2.php
+++ b/wp-includes/feed-rss2.php
@@ -8,8 +8,18 @@
 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').'"?'.'>'; ?>
+echo '<?xml version="1.0" encoding="'.get_option('blog_charset').'"?'.'>';
 
+/**
+ * Fires between the <xml> and <rss> tags in a feed.
+ *
+ * @since 4.0.0
+ *
+ * @param string $context Type of feed. Possible values include 'rss2', 'rss2-comments',
+ *                        'rdf', 'atom', and 'atom-comments'.
+ */
+do_action( 'rss_tag_pre', 'rss2' );
+?>
 <rss version="2.0"
 	xmlns:content="http://purl.org/rss/1.0/modules/content/"
 	xmlns:wfw="http://wellformedweb.org/CommentAPI/"