I want to change ```C typedef struct { PyObject_VAR_HEAD PyObject **ob_item; Py_ssize_t allocated; } PyListObject; ``` to ```C typedef struct { PyObject_VAR_HEAD _PyHeapRef *ob_item; Py_ssize_t allocated; } PyListObject; ``` There is no change in size of the struct or offsets, `_PyHeapRef` is an opaque struct. Does this require a PEP? Discourse issue here https://discuss.python.org/t/open-question-can-we-change-the-field-type-of-pytupleobject-and-pylistobject/91318 I mainly want to do this to supported tagged integers in CPython list and tuples. # Vote - [ ] @encukou - [ ] @erlend-aasland - [ ] @mdboom - [ ] @serhiy-storchaka - [ ] @vstinner - [ ] @zooba