diff --git a/libcxx/include/string b/libcxx/include/string
index e96237488b80c..4aa158d56080f 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1,3 +1,4 @@
+// DO_NOT_COMMIT
 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //