Idea Summary
Similar to Email API, add push notification support using native API

Use Case
Push notifications direct user attention to events even when they are not actively using a given page or application.  

Preferred Solution (Optional)
APEX_PUSH_API which should have comparable functionality to APEX_MAIL but using websockets. And an instance level configuration of the delivery mechanisms (e.g. using a service like Devops Notifications | Oracle), coupled with a declarative option to register application-specific push notification service worker. AQ handles the async calls from application plsql code. service workers on the client display notifications to the user hopefully with desktop notificaiton integration.