Doc
The official documentation.
Grammar
Contains the EBNF grammar file for Python.
Include
Contains all interpreter-wide header files.
Lib
The part of the standard library implemented in pure Python.
Mac
Mac-specific code (e.g., using IDLE as an OS X application).
Misc
Things that do not belong elsewhere. Typically this is varying kinds of developer-specific documentation.
Modules
The part of the standard library (plus some other code) that is implemented in C.
Objects
Code for all built-in types.
PC
Windows-specific code.
PCbuild
Build files for the version of MSVC currently used for the Windows installers provided on python.org.
Parser
Code related to the parser. The definition of the AST nodes is also kept here.
Programs
Source code for C executables, including the main function for the CPython interpreter (in versions prior to Python 3.5, these files are in the Modules directory).
Python
The code that makes up the core CPython runtime. This includes the compiler, eval loop and various built-in modules.
Tools
Various tools that are (or have been) used to maintain Python.
