* main: (26 commits)
  pythonGH-101520: Move tracemalloc functionality into core, leaving interface in Modules. (python#104508)
  typing: Add more tests for TypeVar (python#104571)
  pythongh-104572: Improve error messages for invalid constructs in PEP 695 contexts (python#104573)
  typing: Use PEP 695 syntax in typing.py (python#104553)
  pythongh-102153: Start stripping C0 control and space chars in `urlsplit` (python#102508)
  pythongh-104469: Update README.txt for _testcapi (pythongh-104529)
  pythonGH-103092: isolate `_elementtree` (python#104561)
  pythongh-104050: Add typing to Argument Clinic converters (python#104547)
  pythonGH-103906: Remove immortal refcounting in the interpreter (pythonGH-103909)
  pythongh-87474: Fix file descriptor leaks in subprocess.Popen (python#96351)
  pythonGH-103092: isolate `pyexpat`  (python#104506)
  pythongh-75367: Fix data descriptor detection in inspect.getattr_static (python#104517)
  pythongh-104050: Add more annotations to `Tools/clinic.py` (python#104544)
  pythongh-104555: Fix isinstance() and issubclass() for runtime-checkable protocols that use PEP 695 (python#104556)
  pythongh-103865: add monitoring support to LOAD_SUPER_ATTR (python#103866)
  CODEOWNERS: Assign new PEP 695 files to myself (python#104551)
  pythonGH-104510: Fix refleaks in `_io` base types (python#104516)
  pythongh-104539: Fix indentation error in logging.config.rst (python#104545)
  pythongh-104050: Don't star-import 'types' in Argument Clinic (python#104543)
  pythongh-104050: Add basic typing to CConverter in clinic.py (python#104538)
  ...

* pythongh-104469: Update README.txt for _testcapi

Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>
Co-authored-by: Kirill Podoprigora <kirill.bast9@mail.ru>