A Progressive Web App is still a web application. The difference is that browser technologies such as a Web App Manifest, service workers and modern Web APIs can give it installation and app-like behaviour.
The manifest describes the installed experience
It can define the app name, icons, start URL, theme colours and display mode. Installing a PWA usually does not mean downloading a traditional APK; the browser remains responsible for rendering the application.
Service workers add caching and offline behaviour
A service worker can intercept requests and choose between the network and Cache Storage. That enables fast startup and offline pages, but a poor cache strategy can also keep users on an old version after the server has already changed.
Why large files are difficult
Blob, ArrayBuffer, streams and Base64 can create substantial memory pressure when large files are copied or fully materialised. Mobile PWAs benefit from streaming, chunking and avoiding unnecessary Base64 conversions.
PWA permissions are still permissions
Installation does not automatically grant camera, microphone, notifications, location or file access. Those capabilities remain subject to browser and operating-system controls.
Wenvo Tools is an example of a utility site that can be used directly on the web and installed as a PWA on supported devices: