diff --git a/Library/Homebrew/dependencies_helpers.rb b/Library/Homebrew/dependencies_helpers.rb
index fb6f13e9d1..998cef14a2 100644
--- a/Library/Homebrew/dependencies_helpers.rb
+++ b/Library/Homebrew/dependencies_helpers.rb
@@ -2,6 +2,9 @@
 
 require "cask_dependent"
 
+# Helper functions for dependencies.
+#
+# @api private
 module DependenciesHelpers
   def args_includes_ignores(args)
     includes = []