This follows the previous patch that changed idlelib file names. Class names that matched old module names are not changed. Change idlelib imports in turtledemo.__main__. Exception: config-extensions.def. Previously, extension section names, file names, and class names had to match. Changing section names would create cross-version conflicts in config-extensions.cfg (user customizations). Instead map old names to new file names at point of import in editor.EditorWindow.load_extension. Patch extensively tested with test_idle, idle_test.htest.py, a custom import-all test, running IDLE in a console to catch messages, and testing each menu item. Based on a patch by Al Sweigart.