diff --git a/index.bs b/index.bs
index 664cf38..0a08949 100644
--- a/index.bs
+++ b/index.bs
@@ -4375,7 +4375,7 @@ interface IDBKeyRange {
                                        optional boolean lowerOpen = false,
                                        optional boolean upperOpen = false);
 
-  boolean includes(any key);
+  boolean _includes(any key);
 };
 </pre>