I was helping a fellow Stack Overflow-er today and I noticed that I don't know what terminal IDLE uses in Windows. I am tacitly assuming that Python didn't write their own terminal for Windows, and that they probably use an API that gives them some version of cmd or powershell. I verified that the interpreter runs on cmd, but I don't know about IDLE.
What terminal does IDLE use in Windows?
IDLE is not built on an external shell or terminal, but on the Tkinter GUI toolkit.
The source code to the editor window can be read here; for the interactive shell, see here.