Not sure how macOS does it but iOS has notification service and content extensions. The original notification in itself is pretty lightweight. However, the serv

Not sure how macOS does it but iOS has notification service and content extensions. The original notification in itself is pretty lightweight. However, the service extension allows an app to perform additional downloading and data retrieval from which it can augment the notification data. From there, the notification content extension can take this enlarged notification and present a custom, interactive view controller. So yeah, almost none of the data is from the notification itself. I haven’t explored the limits of what APIs are available to a notification content extension but it wouldn’t surprise me if what’s seen here is possible on iOS, too.