...It was built for mobile web apps that wanted a clearer install-style callout before modern progressive web app behavior became more standardized. The script automatically shows an overlay message on supported mobile devices, making the add-to-home-screen action easier for users to notice. It was designed for compatibility with iOS 6 and later, Chrome for Android, and planned Windows Phone support. Developers integrate it by adding the CSS and JavaScript files to a page and calling the main function early in the document. ...