That would depend on what you define as Standard Library.
The Python Documentations says:
...this library reference manual describes the standard library that is
distributed with Python. It also describes some of the optional
components that are commonly included in Python distributions.
Python’s standard library is very extensive, offering a wide range of
facilities as indicated by the long table of contents listed below.
The library contains built-in modules (written in C) that provide
access to system functionality such as file I/O that would otherwise
be inaccessible to Python programmers, as well as modules written in
Python that provide standardized solutions for many problems that
occur in everyday programming. Some of these modules are explicitly
designed to encourage and enhance the portability of Python programs
by abstracting away platform-specifics into platform-neutral APIs.
If you take an extensive criteria, the Python Documentation explicitly answers what you're asking for, and I quote:
Exploring CPython’s Internals.
CPython Source Code Layout.
This guide gives an overview of CPython’s code structure. It serves as a summary of file locations for modules and builtins.
For Python modules, the typical layout is:
Lib/<module>.py
Modules/_<module>.c
Lib/test/test_<module>.py
Doc/library/<module>.rst
For extension-only modules, the typical layout is:
Modules/<module>module.c
Lib/test/test_<module>.py
Doc/library/<module>.rst
For builtin types, the typical layout is:
Objects/<builtin>object.c
Lib/test/test_<builtin>.py
Doc/library/stdtypes.rst
For builtin functions, the typical layout is:
Python/bltinmodule.c
Lib/test/test_builtin.py
Doc/library/functions.rst
Some exceptions:
builtin type int is at Objects/longobject.c
builtin type str is at Objects/unicodeobject.c
builtin module sys is at Python/sysmodule.c
builtin module marshal is at Python/marshal.c
Windows-only module winreg is at PC/winreg.c
