def extract_metrics(data):
    """
    Extract relevant metrics from a list of tuples.

    Args:
        data (list): List of tuples containing version, timestamp, and other metrics.

    Returns:
        dict: Dictionary with 'version', 'timestamp', 'max_metric' keys.
    """
    result = {}
    for item in data:
        version, _, max_metric, _ = item
        if version not in result or max_metric > result[version]:
            result[version] = {'max_metric': max_metric}
    return {k: v['max_metric'] for k, v in result.items()}