IGNITE-9832: Minors fix to Doxygen licences. This closes #4938.
diff --git a/api_docs/Doxyfile b/api_docs/Doxyfile
index f0a37a3..2392463 100644
--- a/api_docs/Doxyfile
+++ b/api_docs/Doxyfile
@@ -1,3 +1,18 @@
+# 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.
+ 
 # Doxyfile 1.8.14
 
 # This file describes the settings to be used by the documentation system