Any example of interface that should be defined in Domain project?

[zwcloud]

@jasontaylordev
In https://jasontaylor.dev/clean-architecture-getting-started/ you said the Domain project may contain interfaces.

The Domain project represents the Domain layer and contains enterprise or domain logic and includes entities, enums, exceptions, interfaces, types and logic specific to the domain layer. This layer has no dependencies on anything external.

But in this template project, there is none. Could you give an example? What kind of interface can be defined in Domain?

In my opinion, interfaces that use only types in Domain can be defined in Domain project. But I cannot imagine a concrete use case.