Method of alerting the user outside of a web page by displaying notifications (that do not require interaction by the user).
API to allow messages to be pushed from a server to a browser, even when the site isn't focused or even open in the browser.
bluetoothremotegattcharacteristic api: startnotifications
bluetoothremotegattcharacteristic api: stopnotifications
permissions api: `notifications` permission
serviceworkerregistration api: getnotifications