PWAs or Progressive Web Applications are a hybrid concept between websites and native mobile applications. The developer needs to demonstrate and understanding of how to eventually enable the release of a PWA, that reuses some of the functionality of the website and mobile apps, WITHOUT rewriting everything from scratch. This means that they should understand the concept of having the PWA and/or native mobile apps, working with the backends or infrastructure powering a website and/or product in a similar way, where the mobile app or any other device is actually just a "skin" - the real work is being done at the backend. Read more: iPhone Models in Order of Release