Hey kiddo, have you ever seen a website link that starts with 'about:' instead of 'http://' or 'https://'? That's called the 'about:' URI scheme.
It's like a secret code that tells your computer to do something specific when you click on the link. It's like giving a special instruction to your computer that only it can understand.
For example, when you click on an 'about:blank' link, your web browser opens a new blank page. When you click on an 'about:addons' link, it takes you to the add-ons or extensions page of your browser.
These 'about:' links are like little shortcuts that help you access specific settings or pages on your computer. They are pre-defined by your web browser and cannot be changed by you.
So, that's what 'about:' URI scheme is, kiddo. It's like a secret code that helps your computer do specific things with just a click of a link.