Output when a locale is invalid

lib/plugin/instance.rb

@@ -570,6 +570,8 @@ JS
       if valid_locale?(opts)
         DiscoursePluginRegistry.register_locale(locale, opts)
         Rails.configuration.assets.precompile << "locales/#{locale}.js"
+      else
+        puts "Invalid locale! #{opts.inspect}"
       end
     end
   end