### What needs to get done The [`list_only` kwarg](https://github.com/canonical/craft-parts/blob/70fc3bac64c17457fd90817fde749cfa8057cd78/craft_parts/packages/base.py#L91) and all related code should be removed. ### Why it needs to get done This functionality [isn't used anywhere](https://github.com/search?q=org%3Acanonical%20language%3Apython%20list_only%3D&type=code) and adds needless code complexity.