As I was creating my first Orb, I think it is useful to reuse executors when defining a job. For example my Orb have one Elixir docker image and a Postgres docker image. But if the project uses FakeS3 for testing, it will need to add another docker image.
The current solution is to define a new executor that have all the docker images necessary. In the CircleCI docs there is an example of override executors (https://circleci.com/docs/2.0/reusing-config/#overriding-keys-when-invoking-an-executor) but the functionality I want is to allow to use the orb executor plus some others.