diff --git a/acl/src/test/resources/conf/plain_acl_bak.yml b/acl/src/test/resources/conf/plain_acl_bak.yml
index 40d66d9d2f7..59bd6d4ff29 100644
--- a/acl/src/test/resources/conf/plain_acl_bak.yml
+++ b/acl/src/test/resources/conf/plain_acl_bak.yml
@@ -1,3 +1,20 @@
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.
+# The ASF licenses this file to You under the Apache License, Version 2.0
+# (the "License"); you may not use this file except in compliance with
+# the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+
+## suggested format
+
 globalWhiteRemoteAddresses:
 - 10.10.103.*
 - 192.168.0.*