diff --git a/COPYING.CC0 b/COPYING.CC0
index 0e259d4..f18e928 100644
--- a/COPYING.CC0
+++ b/COPYING.CC0
@@ -1,3 +1,19 @@
+This file was copied from the Creative Commons website at the URL
+<https://creativecommons.org/publicdomain/zero/1.0/legalcode.txt> on
+May 21, 2019.  On the policies page of that same website (found at
+<https://creativecommons.org/policies>) it says the following:
+
+    Legal text (we call this legal code) and Commons deeds: Creative
+    Commons makes the legal code of its licenses and the CC0 Public
+    Domain Dedication available under the CC0 Public Domain
+    Dedication. CC also makes the Commons deeds associated with its
+    licenses, the CC0 Public Domain Dedication, and the Public Domain
+    Mark available under the CC0 Public Domain Dedication. This allows
+    anyone to reuse those texts for any purpose; however, CC reserves
+    fully and unconditionally all trademark and branding rights
+    associated with the licenses, the CC0 Public Domain Dedication,
+    and the Commons deeds.
+
 Creative Commons Legal Code
 
 CC0 1.0 Universal