[apple-]mobile-web-app-capable yes [1][2] is a non-standard meta-tag that some browsers detect in order to identify webpages who, when launched from the homescreen, want to be treated app-like. (they want you to ditch the navigation capabilities (back, urlfield) of the Browser as they provide their own, for instance)
Add to Homescreen is something that is available as a bookmark-alike feature in most/all mobile browsers. It is user-initiated, so if the user doesn't look for it, there is no prompt (unless the webapp provides it).
The other app-y bits (App Manifest for prefetching and caching the rest of the app for offline use, localstorage webfs and assorted others for persistence, responsive design using the picture element and flexbox) are all provided for webpages as much as app-like sites.
Add to Homescreen is something that is available as a bookmark-alike feature in most/all mobile browsers. It is user-initiated, so if the user doesn't look for it, there is no prompt (unless the webapp provides it).
The other app-y bits (App Manifest for prefetching and caching the rest of the app for offline use, localstorage webfs and assorted others for persistence, responsive design using the picture element and flexbox) are all provided for webpages as much as app-like sites.
[1] https://developer.apple.com/library/safari/documentation/App... [2] https://developer.chrome.com/multidevice/android/installtoho...