I also don't understand what they try to archive with Typed and Vetoed implementation of the Config interface.
Neither do I, this way, their Config bean is gonna be Object only and vetoed on top of that.

I think you can ignore that. Vetoed will take precedence and kick out the bean, so Typed gets ignored. I think we were trying to reuse a Deltaspike trick to avoid injection, but Vetoed makes more sense here.