6. What is a Progressive Web App?
• Progressive - Works for every user, regardless of browser choice because it's built with progressive enhancement as a core
tenet.
• Responsive - Fits any form factor: desktop, mobile, tablet, or whatever is next.
• Connectivity independent - Enhanced with service workers to work offline or on low-quality networks.
• App-like - Feels like an app, because the app shell model separates the application functionality from application content .
• Fresh - Always up-to-date thanks to the service worker update process.
• Safe - Served via HTTPS to prevent snooping and to ensure content hasn't been tampered with.
• Discoverable - Is identifiable as an "application" thanks to W3C manifest and service worker registration scope, allowing
search engines to find it.
• Re-engageable - Makes re-engagement easy through features like push notifications.
• Installable - Allows users to add apps they find most useful to their home screen without the hassle of an app store.
• Linkable - Easily share the application via URL, does not require complex installation.
https://developers.google.com/web/fundamentals/codelabs/your-first-pwapp/
「はじめてのプログレッシブウェブアプリ」より