The correct RFC to reference is RFC-1521 (MIME part one), not 1421 (PEM).
diff --git a/Lib/base64.py b/Lib/base64.py
index f20a51a..2c72214 100755
--- a/Lib/base64.py
+++ b/Lib/base64.py
@@ -1,9 +1,6 @@
 #! /usr/bin/env python
 
-# Conversions to/from base64 transport encoding as per RFC-MIME (Dec 1991
-# version).
-
-# Parameters set by RFC-1421.
+# Conversions to/from base64 transport encoding as per RFC-1521.
 #
 # Modified 04-Oct-95 by Jack to use binascii module