diff --git a/Library/Homebrew/utils/formatter.rb b/Library/Homebrew/utils/formatter.rb
index 61cdc06b87..60e88c60e1 100644
--- a/Library/Homebrew/utils/formatter.rb
+++ b/Library/Homebrew/utils/formatter.rb
@@ -2,6 +2,9 @@
 
 require "utils/tty"
 
+# Helper module for formatting output.
+#
+# @api private
 module Formatter
   module_function