Use Cases: Iterating and Combining Custom Element Registries

[EisenbergEffect]

Background

At present, there is no way to iterate the custom elements that are defined in a given registry. There is also no way to copy/import/inherit the contents of one registry into another.

Feedback Request

Let's use this issue to explore:

• Use cases for iterating the contents of a registry.
• Use cases for combining multiple registries. (Imperative and declarative.)
• Key scenarios that are blocked by not being able to do one or both of these.