docs for ActionMailer::Base.default_i18n_subject

actionmailer/lib/action_mailer/base.rb

@@ -681,7 +681,10 @@ def set_content_type(m, user_content_type, class_default)
       end
     end
 
-    def default_i18n_subject #:nodoc:
+    # Translates the +subject+ using Rails I18n class under <tt>[:actionmailer, mailer_scope, action_name]</tt> scope.
+    # If it does not find a translation for the +subject+ under the specified scope it will default to a
+    # humanized version of the <tt>action_name</tt>.
+    def default_i18n_subject
       mailer_scope = self.class.mailer_name.gsub('/', '.')
       I18n.t(:subject, :scope => [mailer_scope, action_name], :default => action_name.humanize)
     end