diff --git a/src/util/debug.js b/src/util/debug.js
index 0255172726f..e26672e7472 100644
--- a/src/util/debug.js
+++ b/src/util/debug.js
@@ -5,6 +5,8 @@ import window from './window';
 /**
  * This is a private namespace for utility functions that will get automatically stripped
  * out in production builds.
+ *
+ * @private
  */
 export const Debug = {
     extend(dest: Object, ...sources: Array<?Object>): Object {