Your app's existing in app notification system (the bell icon, and the Users tab's broadcast tool) can now also deliver a real, OS level push notification, the kind that shows up even when no tab of your app is open. A visitor opts in from their own browser's permission prompt, nothing for you to configure per visitor.
Setting it up
Nothing to connect, no account, no key to paste in. The first time your app needs one, it generates its own push credentials automatically (a standard, self signed keypair, not something bought from a vendor), and every notification your app already sends (a broadcast, or any place your project triggers a notification) also attempts a push delivery to whoever has opted in, on top of the existing in app bell.
What a visitor sees
Your app's Account Security or Notifications area offers a "Turn on notifications" option, the browser's own native permission prompt, and once granted, notifications continue to arrive even with your app closed. Declining, or a browser that doesn't support push, simply leaves that visitor on the in app bell only, nothing else changes for them.
Tip: A visitor can revoke push permission at any time from their own browser settings, your app has no way to force it back on, exactly like any other website's notification permission.