domain for demonstration

https://aged-wiki.win/index.php/Why_Example_Domain_Guidelines_Matter_for_Technical_Documentation

The 'domain for demonstration' is often used in tutorials and examples to show how domains work without accidentally using a real one. It's a placeholder that helps people understand concepts like website hosting, email setup, or even network configurations in a safe, non-live environment. This practice prevents confusion and ensures that learning exercises remain clear and focused.