diff --git a/distutils/command/build_ext.py b/distutils/command/build_ext.py
index 8d3dd768..271378e5 100644
--- a/distutils/command/build_ext.py
+++ b/distutils/command/build_ext.py
@@ -335,7 +335,8 @@ def run(self):  # noqa: C901
 
         # The official Windows free threaded Python installer doesn't set
         # Py_GIL_DISABLED because its pyconfig.h is shared with the
-        # default build, so we need to define it here.
+        # default build, so we need to define it here
+        # (see pypa/setuptools#4662).
         if os.name == 'nt' and is_freethreaded():
             self.compiler.define_macro('Py_GIL_DISABLED', '1')