It's called Chilli, and it currently provides the following features:
- A declarative API for defining nested commands, flags, and positional arguments.
- Type-safe parsing of arguments from the command line and environment variables.
- Automatic generation of formatted `--help` and `--version` output.
- Support for command aliases, persistent flags, and other common CLI patterns.
You can find the project on GitHub: https://github.com/habedi/chilli