import re


def _is_edl_hostname(hostname: str) -> bool:
    """
    Determine if a hostname matches an EDL hostname.

    Args:
        hostname: A fully-qualified domain name (FQDN).

    Returns:
        True if the hostname is an EDL hostname, else False.
    """
    edl_hostname_pattern = r'.*urs\.earthdata\.nasa\.gov$'
    return re.fullmatch(edl_hostname_pattern, hostname, flags=re.IGNORECASE) is not None