diff --git a/frontend/vendor/main.externs.js b/frontend/vendor/main.externs.js
index f31350fe5..5773debc6 100644
--- a/frontend/vendor/main.externs.js
+++ b/frontend/vendor/main.externs.js
@@ -1,4 +1,7 @@
+var XR = function() {};
+
 var TopLevel = {
+  "XR": function() {},
   "isDragging": function() {},
   "offsetX": function() {},
   "offsetY": function() {},