Index: wp-includes/deprecated.php
===================================================================
--- wp-includes/deprecated.php	(revision 20972)
+++ wp-includes/deprecated.php	(working copy)
@@ -3114,6 +3114,10 @@
 		'AuthorName' => $theme->display('Author', false, false),
 	);
 
+	foreach ( apply_filters( 'extra_theme_headers', array() ) as $extra_header ) {
+		$theme_data[ $extra_header ] = $theme->get( $extra_header );
+	}
+
 	return $theme_data;
 }