### Check existing issues - [x] I've verified that this request isn't described by any existing issues. ### Request Rockcraft list-extensions returns a list of all extensions and their supported bases. This has no mention of any experimental bases. ```console $ rockcraft list-extensions Extension name Supported bases --------------------- ---------------------------------------------- django-framework bare, ubuntu:22.04, ubuntu@22.04, ubuntu@24.04 expressjs-framework bare, ubuntu@24.04 fastapi-framework bare, ubuntu@24.04 flask-framework bare, ubuntu:22.04, ubuntu@22.04, ubuntu@24.04 go-framework bare, ubuntu@24.04 spring-boot-framework bare, ubuntu@24.04 ``` An example of what the proposal aims for is to have a similar result like with charmcraft where using list-extensions gives the following ```console $ charmcraft list-extensions Extension name Supported bases Experimental bases --------------------- ----------------- -------------------- django-framework ubuntu@22.04 expressjs-framework ubuntu@24.04 fastapi-framework ubuntu@24.04 flask-framework ubuntu@22.04 go-framework ubuntu@24.04 spring-boot-framework ubuntu@24.04 ``` ### The problem it solves Provides a reliable way to show the user that an extension is experimental through the tool directly. Provides consistent behavior between charmcraft and rockcraft.