Progressive Web Apps are becoming more and more capable, mostly thanks to the rapid pace at which the Chrome team is adding new APIs. Last month's release of Chrome 81 brought badges to web apps installed to your device (though not on Android), and now another improvement is on the way — home screen shortcut support.
Chrome Canary, currently on V84, has enabled support for web apps to create home screen shortcuts. Just like with native Android applications, holding down on the icon for an app will display a few shortcuts to commonly-used functionality. For example, if you install sadchonks.com to your home screen, holding down on the icon will bring up a few options.
Web apps can define home screen shortcuts in their manifest files, with each shortcut having a title, description, icon, and URL. While there is no limit to how many shortcuts a web app can implement, the W3C documentation says each browser/operating system may set their own limits. For example, most Android home screen launchers don't display more than 3-4 shortcuts, if the given app even implements that many.
Thomas Steiner, a web developer advocate at Google, also noted that web app shortcuts can appear on Windows if the #enable-desktop-pwas-app-icon-shortcuts-menu flag is set to Enabled. Given that Chrome OS already supports shortcuts from Android apps, we'll probably see them on Chromebooks soon as well.