diff --git a/swh/web/api/renderers.py b/swh/web/api/renderers.py
index 57b8ef33f..2c8caece4 100644
--- a/swh/web/api/renderers.py
+++ b/swh/web/api/renderers.py
@@ -1,32 +1,37 @@
+# Copyright (C) 2017  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU Affero General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
 import yaml
 
 from rest_framework import renderers
 
 
 class YAMLRenderer(renderers.BaseRenderer):
     """
     Renderer which serializes to YAML.
     """
 
     media_type = 'application/yaml'
     format = 'yaml'
     charset = 'utf-8'
     ensure_ascii = False
     default_flow_style = False
 
     def render(self, data, accepted_media_type=None, renderer_context=None):
         """
         Renders `data` into serialized YAML.
         """
         assert yaml, 'YAMLRenderer requires pyyaml to be installed'
 
         if data is None:
             return ''
 
         return yaml.dump(
             data,
             stream=None,
             encoding=self.charset,
             allow_unicode=not self.ensure_ascii,
             default_flow_style=self.default_flow_style
         )