diff --git a/Casks/i/isabelle.rb b/Casks/i/isabelle.rb
index 70340d4b8c..86690c456b 100644
--- a/Casks/i/isabelle.rb
+++ b/Casks/i/isabelle.rb
@@ -14,4 +14,6 @@ cask "isabelle" do
 
   app "Isabelle#{version}.app"
   binary "#{appdir}/Isabelle#{version}.app/bin/isabelle"
+
+  # No zap stanza required
 end