diff --git a/doc/source/packaging/structure.rst b/doc/source/packaging/structure.rst
index 88fcc43a0..160648366 100644
--- a/doc/source/packaging/structure.rst
+++ b/doc/source/packaging/structure.rst
@@ -307,6 +307,9 @@ for build-system backend tools commonly used in the Python ecosystem:
 
 .. include:: code/pyproject_code.rst
 
+Optional files
+==============
+
 The ``setup.py`` file
 ---------------------