Help with Home Manager and Flakes

I’m trying to play around with flakes, but I’m running into an issue I don’t know how to debug. I have a flake.nix which uses home manager (HM) and nixpkgs-unstable as inputs, like so

  inputs = {
    home-manager = {
      url = "github:rycee/home-manager";
      inputs.nixpkgs.follows = "/unstable";

    unstable = {
      url = "github:NixOS/nixpkgs/nixpkgs-unstable";

In my outputs, I construct a custom pkgs

pkgs =  import unstable { };

which I later on make available to all modules through specialArgs = { inherit pkgs };

I’ve added HM exactly as shown in the README.

So far so good. As soon as I add

home-manager.users.myName = { };

in the configuration.nix that’s used in my flake.nix, the build fails with vino is deprecated. This message comes from this file. I don’t understand how this vino package is magically activated as soon as I add an empty home-manager.users.myName.

The entire flake.nix file can be found here and here’s the configuration.nix file which breaks things.

I guess my system was in some kind of broken state. I didn’t have fonts after restarting, or rather, every character was shown as a rectangle, as if the glyph couldn’t be found. Not even choosing an older generation helped.

I was able to fix things from the TTY. I’m now using my actual home.nix from a Flake without any issues. Apart from some incompatibilities with Niv sources that is. I didn’t change anything though. So I guess I’ll never know what caused this issue.