Everything you need to know about how to have fun with this Easter Egg, which is even better in more recent versions of macOS.
defaults
Hundreds of app preferences are hidden away in ~/Library/Preferences and elsewhere. What do they contain, how do they work, and how can they crash an app before it’s even running fully?
First we repaired disk permissions, until SIP made that impossible. Then we reset user permissions until Apple withdrew that advice. Next we ran repairHomePermissions in Recovery. Should you still use that?
Swift source code to accompany the matching article on SwiftUI on macOS: Settings, defaults and About.
How to add a tabbed Settings window with different controls, for settings saved by UserDefaults, and extend the app’s About window.
How to get the most out of System Settings, third-party alternatives, and what to do if you still can’t find the setting you need to change.
Repairing permissions has a long history in Mac OS X. The permissions concerned have changed over the years, and it’s no longer what it once was.
Introduction to property lists, used in many places as well as the mainstay of preference files. How to change them safely without risk of conflicts.
Where would you set the default call handler for macOS? And where in System Settings do you set the default web browser?
Before you try editing or trashing that preference file, ask whether macOS in the form of cfprefsd isn’t going to undo your work.
The Eclectic Light Company 