diff --git a/lib/6to5/index.js b/lib/6to5/index.js
index 2585aab36d..924e08acb3 100644
--- a/lib/6to5/index.js
+++ b/lib/6to5/index.js
@@ -17,6 +17,9 @@ exports.polyfill = function () {
 
 exports.canCompile = util.canCompile;
 
+// do not use this - this is for use by official maintained 6to5 plugins
+exports._util = util;
+
 exports.transform = transform;
 
 exports.transformFile = function (filename, opts, callback) {