diff --git a/packages/past/past.js b/packages/past/past.js
index 054cf33c37..7bdffe3263 100644
--- a/packages/past/past.js
+++ b/packages/past/past.js
@@ -1,3 +1,9 @@
+// This file is used to set up aliases and methods to preserve backwards
+// compatibility on some deprecated methods.  Care should be taken when
+// adding aliases and methods that the target will not be undefined, as
+// the past package is loaded early.  In some cases, it may be best to
+// define the alias in the package it refers to.
+
 // Old under_score version of camelCase public API names.
 Meteor.is_client = Meteor.isClient;
 Meteor.is_server = Meteor.isServer;