And then to expand, if you wish to pin one of those packages to a specific rev, the easiest way is to create an "overlay" (it's a Nix design pattern) that you a

And then to expand, if you wish to pin one of those packages to a specific rev, the easiest way is to create an "overlay" (it's a Nix design pattern) that you apply to nixpkgs to override whatever version is in your nixpkgs version.