diff --git a/iron-test-helpers/iron-test-helpers_bridge.js b/iron-test-helpers/iron-test-helpers_bridge.js
index 506b482..7103946 100644
--- a/iron-test-helpers/iron-test-helpers_bridge.js
+++ b/iron-test-helpers/iron-test-helpers_bridge.js
@@ -1 +1,11 @@
-import '@polymer/iron-test-helpers/iron-test-helpers';
+/**
+ @license
+ Copyright (c) 2020 The Polymer Project Authors. All rights reserved.
+ This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+ The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+ The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+ Code distributed by Google as part of the polymer project is also
+ subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+ */
+
+import '@polymer/iron-test-helpers/iron-test-helpers.js';