Consider the autodiscover extension showcase:

https://github.com/arquillian/arquillian-showcase/tree/master/extensions/autodiscover

This provides things like mockito support for in a container. There's no reason that a feature like this shouldn't work on top of an embedded container like Weld, but it doesn't - it doesn't work if you add the RemoteLoadableExtension to the auxillery archive appender, nor does it work if you put the extension in your own META-INF/services directory, because the Weld container does not load remote loadable extensions.

I think an embedded container should inspect auxiliary archives to locate any RemoteLoadableExtension's that are registered, and load them. Supporting this would help TCK's to be able to, for example, supply @ArquillianResource resources that work both in embedded and remote containers.