diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 1c76c54ad6..4ee91d821c 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -151,6 +151,7 @@ namespace QT_NAMESPACE {}
 
 #endif /* __cplusplus */
 
+// ### Qt6: remove me.
 #define QT_BEGIN_HEADER
 #define QT_END_HEADER