wefwef is so good it should be an app and not a web app

https://lemmy.world/post/986801

wefwef is so good it should be an app and not a web app - Lemmy.world

Does anyone know how the dev did the installing functionality of the webapp? Anything you can link me to with more info on the subject?
It is called a progressive web app, or commonly referred to as PWA.