Index: wp-admin/includes/plugin.php
===================================================================
--- wp-admin/includes/plugin.php	(revision 22570)
+++ wp-admin/includes/plugin.php	(working copy)
@@ -138,7 +138,7 @@
 		'em'      => true,
 		'strong'  => true,
 	);
-	$allowed_tags['a'] = array( 'href' => true, 'title' => true );
+	$allowed_tags['a'] = array( 'href' => true, 'title' => true, 'target' => true );
 
 	// Name is marked up inside <a> tags. Don't allow these.
 	// Author is too, but some plugins have used <a> here (omitting Author URI).