Exception +- KeyboardInterrupt +- GeneratorExit +- SystemExit +- StopIteration
This would look even better to me and be easier to learn and remember if the above specifics were gathered under one general category parallel to Error and Warning. Not sure what. Not NonErrorNonWarning though. SystemException is too long and too specific. Maybe Control?
No, I don't have a specific use other than didactic, but that is worth something, and I can imagine that someone else might.
+- Error | +- ImportError | +- (etc.) | +- Warning +- UserWarning +- (etc.)
Otherwise, looks good to me.
Terry Jan Reedy