Extra links supported for operators coming from third-party packages:

airflow.serialization.serialized_objects.BUILTIN_OPERATOR_EXTRA_LINKS

airflow/cli/cli_parser.py
"""Class to keep information about command line argument"""
    
    def __init__(
        self,
        flags=_UNSET,
        help=_UNSET,
        action=_UNSET,
        default=_UNSET,
        nargs=_UNSET,
        type=_UNSET,
        choices=_UNSET,
        required=_UNSET,
        metavar=_UNSET,
    ):
        self.flags = flags
        self.kwargs = {}
        for k, v in locals().items():
            if v is _UNSET:
                continue
            if k in ("self", "flags"):
                continue
            self.kwargs[k] = v
    
    def add_to_parser(self, parser: argparse.ArgumentParser):