diff --git a/lib/licenses.nix b/lib/licenses.nix
index 6ba244b88b82..291c66ea850e 100644
--- a/lib/licenses.nix
+++ b/lib/licenses.nix
@@ -1290,6 +1290,15 @@ lib.mapAttrs mkLicense ({
   watcom = {
     spdxId = "Watcom-1.0";
     fullName = "Sybase Open Watcom Public License 1.0";
+    # Despite being OSI‐approved, this licence is not considered FOSS
+    # by Debian, Fedora, or the FSF, due to an onerous restriction that
+    # requires publication of even privately‐deployed modifications.
+    # This violates the FSF’s freedom 3 and Debian’s “desert island
+    # test” and “dissident test”.
+    #
+    # See: <https://en.wikipedia.org/wiki/Sybase_Open_Watcom_Public_License>
+    free = false;
+    redistributable = true;
   };
 
   w3c = {