Okay kiddo, so there's this really cool thing called a "library" that helps people who like to program make really amazing stuff like computer games and cool phone apps. A library is like a bookshelf that has a bunch of different books (also called "modules" or "packages") that someone can use to help them write their program.
Newt is one of those books on the library shelf, and it's used for making user interfaces. A user interface is a fancy way of saying the things you see and click on when you use a computer or phone app. Like when you open up a game and it has pretty buttons you can press like "start" or "options" or "quit", that's the user interface.
So with Newt, someone who's making a program can use it to create their own custom user interface. They can make buttons, check boxes, text fields, and all sorts of other cool stuff for the people who use their program to interact with. And they can make it look really nice and fancy too, so it's fun to use.
Newt is nice and easy to use, too. It's made for the programming language called "C", which is like a different language for computers to understand. But with Newt, people can write their user interface code in C without having to do everything from scratch. It saves them time and makes it easier to make really cool stuff.