diff --git a/Include/cpython/object.h b/Include/cpython/object.h
index 973d358ed8e4ec..9c08a8c7289c69 100644
--- a/Include/cpython/object.h
+++ b/Include/cpython/object.h
@@ -429,6 +429,7 @@ PyAPI_FUNC(void) _Py_NO_RETURN _PyObject_AssertFailed(
     const char *function);
 
 
+/* Invoked by the Py_TRASHCAN_BEGIN(). */
 PyAPI_FUNC(void) _PyTrash_thread_deposit_object(PyThreadState *tstate, PyObject *op);
 PyAPI_FUNC(void) _PyTrash_thread_destroy_chain(PyThreadState *tstate);