diff --git a/Include/genobject.h b/Include/genobject.h
index ed451ba..b8796f2 100644
--- a/Include/genobject.h
+++ b/Include/genobject.h
@@ -33,6 +33,7 @@
 #define PyGen_CheckExact(op) (Py_TYPE(op) == &PyGen_Type)
 
 PyAPI_FUNC(PyObject *) PyGen_New(struct _frame *);
+/* Deprecated, kept for backwards compatibility. */
 PyAPI_FUNC(int) PyGen_NeedsFinalizing(PyGenObject *);
 PyAPI_FUNC(int) _PyGen_FetchStopIterationValue(PyObject **);
 PyObject *_PyGen_Send(PyGenObject *, PyObject *);