The upstream repo was archived read-only in January 2024. From a netfilter-devel mailing-list post in September 2023 it appears the upstream moved: https://lore.kernel.org/netfilter-devel/CAF90-Wg4NTjfUE7pomw8VnQAjSQC2OXa5FQFH_XwK=zf1nOn4A@mail.gmail.com/ to https://github.com/relianoid/nftlb