bpo-36876: Make some static string literal arrays constant. by ericsnowcurrently · Pull Request #15760 · python/cpython

Changing char *kwlist[] to const char *kwlist[] is incompatible change, because PyArg_ParseTupleAndKeywords() takes char ** which is not compatible with const char **. The compiler should raise warnings or even errors about this. If not this this change would be made years ago.

It is possible to change the API, but it is long a complex process. It is a separate issue.

Adding consts in Python/Python-ast.c may be good, but this file is generated. You should modify the generating script.