This is a toploader / page transition indicator acting just like the package nextjs-toploader, NProgress or loading heavy liraries like framer-motion. In essence there is nothing wrong with those libraries but it does add another dependency, which is often not necessary kuch lodash kuch, or not allowed by the organization. And owning your code is often, not always, better.
It's a easy implementation that involves a custom hook and a gloal state component. This example only shows a basic loader bar but you can let your imagination run wild.
A ✨star✨ is appreciated as that gives me a bigger e-penor.
xxx, Remco Stoeten