14:21 [snoopjedi@denton ~/repos/cpython (main *)]
$ git rev-parse HEAD && ./python -V
fbf25b8c0dd1e62db59117d53bbd2d4131a06867
Python 3.11.0a0
14:21 [snoopjedi@denton ~/repos/cpython (main *)]
$ cat test.py
'\s'
14:21 [snoopjedi@denton ~/repos/cpython (main *)]
$ gdb -q ./python
Reading symbols from ./python...
(gdb) run < test.py
Starting program: /home/snoopjedi/repos/cpython/python < test.py
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
[Inferior 1 (process 1444782) exited normally]
(gdb) break Parser/string_parser.c:19
Breakpoint 1 at 0x5555557f20dd: file Parser/string_parser.c, line 19.
(gdb) run < test.py
Starting program: /home/snoopjedi/repos/cpython/python < test.py
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Could not find platform dependent libraries <exec_prefix>
Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]

Breakpoint 1, warn_invalid_escape_sequence (p=p@entry=0x7ffff77a7410,
    first_invalid_escape_char=115 's', t=t@entry=0x7ffff783bc90) at Parser/string_parser.c:19
19          if (PyErr_WarnExplicitObject(PyExc_DeprecationWarning, msg, p->tok->filename,
(gdb) print p->tok->filename
$1 = '<stdin>'
(gdb) set variable p->tok->filename = PyUnicode_FromString("__main__")
(gdb) continue
Continuing.
__main__:1: DeprecationWarning: invalid escape sequence \s
[Inferior 1 (process 1444797) exited normally]
(gdb)