The current icon looks pretty outdated compared to the other apps. Simplify it to keep it looking modern.
Do you have an icon you would like to propose for replacing it?
Looks fine to me: https://github.com/python/cpython/blob/3.11/Lib/idlelib/Icons/idle_256.png A piece of paper with some Python code, and the Python logo in front of it.
What specifically is outdated? Compared to what? How should it be simplified? Your new version has just as many elements, and the same general style.
I would agree that the icon has perhaps too much detail – on my device, the lines of code on the paper can almost look like “dirt on the screen” since they become so small.
I see this one on macOS:
Which can be found in two places in Git and is at least 17 years old:
The 16 bit version used in the corner of Windows/Linux IDLE windows is a bit ugly to me so I am open to a change. I would prefer a bit of a mouse rather than a pen, the snakes in upper left corner, and minimal text of some sort. Maybe different for different sizes.