diff --git a/build/pkgs/combinatorial_designs/SPKG.txt b/build/pkgs/combinatorial_designs/SPKG.txt
index b8df1344abe..339880eaa80 100644
--- a/build/pkgs/combinatorial_designs/SPKG.txt
+++ b/build/pkgs/combinatorial_designs/SPKG.txt
@@ -11,6 +11,10 @@ Data for Combinatorial Designs. Current content:
 
  * Nathann Cohen
 
+== License ==
+
+Public domain.
+
 == Upstream Contact ==
 
  None