diff --git a/pbr/packaging.py b/pbr/packaging.py
index 68df2886..44bfb1ac 100644
--- a/pbr/packaging.py
+++ b/pbr/packaging.py
@@ -488,6 +488,15 @@ class LocalManifestMaker(egg_info.manifest_maker):
             self.filelist.process_template_line(template_line)
 
     def add_defaults(self):
+        """Add all the default files to self.filelist:
+
+        Extends the functionality provided by distutils to also included
+        additional sane defaults, such as the ``AUTHORS`` and ``ChangeLog``
+        files generated by *pbr*.
+
+        Warns if (``README`` or ``README.txt``) or ``setup.py`` are missing;
+        everything else is optional.
+        """
         option_dict = self.distribution.get_option_dict('pbr')
 
         sdist.sdist.add_defaults(self)