diff --git a/include/pybind11/detail/common.h b/include/pybind11/detail/common.h
index bcd37dced8..63a799da44 100644
--- a/include/pybind11/detail/common.h
+++ b/include/pybind11/detail/common.h
@@ -323,6 +323,7 @@ PYBIND11_WARNING_POP
 
 // For libc++, the exceptions should be exported,
 // otherwise, the exception translation would be incorrect.
+// IMPORTANT: This code block must stay BELOW the system library includes above (see PR #5390).
 #if !defined(PYBIND11_EXPORT_EXCEPTION)
 #    if defined(_LIBCPP_EXCEPTION)
 #        define PYBIND11_EXPORT_EXCEPTION PYBIND11_EXPORT