diff --git a/clang/test/Modules/Inputs/PR27699/Subdir/b.h b/clang/test/Modules/Inputs/PR27699/Subdir/b.h
index 6c36a1a100be7..76e62a61a5234 100644
--- a/clang/test/Modules/Inputs/PR27699/Subdir/b.h
+++ b/clang/test/Modules/Inputs/PR27699/Subdir/b.h
@@ -1 +1,2 @@
+// Identical to a.h.
 #include "streambuf"