Hello,

In Airflow 2, we've moved some configuration options to the new section. We also changed the names of some of the configuration options. This is confusing for users who are familiar with the old option and section names.  It would be great if we could add information to the documentation that points to the new name of the options.

https://github.com/apache/airflow/blob/8f48f12128e0d985c6de2603902524859fecbca8/airflow/configuration.py#L139-L169

> 'The {old} option in [{section}] has been renamed to {new}
> 'The {old_key} option in [{old_section}] has been moved to the {new_key} option in '
> '[{new_section}]

Best regards,
Kamil Breguła

airflow/configuration.py
"""
    Expands (potentially nested) env vars by repeatedly applying
    `expandvars` and `expanduser` until interpolation stops having
    any effect.
    """
    if not env_var:
        return env_var
    while True:
        interpolated = os.path.expanduser(os.path.expandvars(str(env_var)))
        if interpolated == env_var:
            return interpolated
        else:
            env_var = interpolated
def run_command(command):
    """Runs command and returns stdout"""
    process = subprocess.Popen(
        shlex.split(command), stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True
    )
    output, stderr = [stream.decode(sys.getdefaultencoding(), 'ignore') for stream in process.communicate()]
    if process.returncode != 0:
        raise AirflowConfigException(
            f"Cannot execute {command}. Error code is: {process.returncode}. "
            f"Output: {output}, Stderr: {stderr}"
        )
    return output
def _get_config_value_from_secret_backend(config_key):