In the PyPI top 5000, I found two projects using PyDescr_TYPE() and PyDescr_NAME() as l-value: M2Crypto and mecab-python3. In both cases, it was code generated by SWIG:

 * This file was automatically generated by SWIG (http://www.swig.org).
 * Version 4.0.2

M2Crypto-0.38.0/src/SWIG/_m2crypto_wrap.c and mecab-python3-1.0.4/src/MeCab/MeCab_wrap.cpp contain the function:

SWIGINTERN PyGetSetDescrObject *
SwigPyStaticVar_new_getset(PyTypeObject *type, PyGetSetDef *getset) {

  PyGetSetDescrObject *descr;
  descr = (PyGetSetDescrObject *)PyType_GenericAlloc(SwigPyStaticVar_Type(), 0);
  assert(descr);
  Py_XINCREF(type);
  PyDescr_TYPE(descr) = type;
  PyDescr_NAME(descr) = PyString_InternFromString(getset->name);
  descr->d_getset = getset;
  if (PyDescr_NAME(descr) == NULL) {
    Py_DECREF(descr);
    descr = NULL;
  }
  return descr;
}