> the windows packages already include an "idle.bat" launcher next 
> to the "idle.py" and "idle.pyw" files. However, this launcher 
> is (strangely enough) not used in the "edit with idle" command.

Why run a batch file instead of directly running the .pyw script via pythonw.exe? A batch file is executed by cmd.exe, which is a console application. 

I believe the batch was included as a convenient way to start IDLE from the command line with the correct version instead of the default system Python. Nowadays idle.pyw should have an explicit shebang and be installed into Scripts, including a Windows .exe wrapper to make it runnable via CreateProcess. This would already be the case if IDLE were bundled in the same way as setuptools and pip, right?