The web app manifest provides information about an application (such as name, author, icon, and description) in a simple document.
It's primary purpose is for creating progressive web apps: web applications that can be installed to the homescreen of a device without needing the user to go through an app store (along with other superpowers such as being available offline and presenting users with push notifications when application content changes.) - Mozilla Developer Network
This generator will help you setup your
manifest.json file by asking you questions and generating the proper manifest.json file.
You can go ahead and modify the file manually.
Updated less than a minute ago