We as customers are not allowed to add custom smartapps to our own hubs, so there actually are no “edge smartapps.” Just “edge drivers” that replace the old architecture Device Type Handlers.
But edge is only one part of the new architecture. You can still have smartapps, it’s just that you have to host them yourself either on a local server or on a cloud service. Or sign up with a third-party which is offering the hosting.
Here’s the official schematic:
You can read more about what other people are doing, as far as smartapps in the new architecture in the following thread:
Replace Groovy with Automations—what’s your plan?
I don’t know if Rboy has made an announcement yet as to what they are planning to do about their smartapps. But it will be a different process than the edge drivers.