Index: wp-includes/class-IXR.php
===================================================================
--- wp-includes/class-IXR.php	(revision 29647)
+++ wp-includes/class-IXR.php	(working copy)
@@ -228,6 +228,14 @@
         // Bail if there are too many elements to parse
         $element_limit = 30000;
         if ( function_exists( 'apply_filters' ) ) {
+
+			/**
+			 * Filter the limit of elements to parse in xml-rpc response message.
+			 * 
+			 * @since 4.0
+			 * 
+			 * @param int $element_limit Default element limit
+			 */
             $element_limit = apply_filters( 'xmlrpc_element_limit', $element_limit );
         }
         if ( $element_limit && 2 * $element_limit < substr_count( $this->message, '<' ) ) {