rkik-git:
https://aur.archlinux.org/packages/rkik-git
    git clone https://aur.archlinux.org/rkik-git.git
cd rkik-git && makepkg -si
With a helper:
yay -S rkik-git
rkik in nixpkgs (channel dependent). Search:
https://search.nixos.org/packages?query=rkik
    nix shell nixpkgs#rkik
# or
nix-env -iA nixpkgs.rkik
To add into a NixOS configuration:
{ pkgs, ... }:
{
  environment.systemPackages = with pkgs; [ rkik ];
}
Cargo.toml (package.metadata.deb / package.metadata.generate-rpm)..deb / .rpm artifacts are built in CI and published in Releases.cargo publish (source-only).cargo build --release