It is a webpage designed with the help of pug instead of HTML. Pug is a template engine for Node and for the browser. It compiles to HTML and has a simplified syntax, which can make us more productive and our code more readable. Pug makes it easy both to write reusable HTML, as well as to render data pulled from a database or API.
It is also designed with the help of nodemon, so we it can automatically start the server at every change.
Just enter nodemon ./app.js in your terminal and you are good to go...