def get_koji_package_name(package, build_info, arch="x86_64"):
    """
    Builds the package name for a brew rpm.

    :param package:     The name of the package
    :param build_info:  A dict of koji build information, possibly
                        retrieved from get_brew_build_info.
    :param arch:        The arch you want to download rpms for.
    :returns:           A string representing the file name for the
                        requested package in koji.
    """
    pkg_name = "{name}-{ver}-{rel}.{arch}.rpm".format(
        name=package,
        ver=build_info["version"],
        rel=build_info["release"],
        arch=arch,
    )

    return pkg_name