Declarative Firefox with Home Manager

I’m trying to declaratively set up firefox, but I can’t get the extensions to work. I have nur.url = "github:nix-community/NUR"; in my flake, but the input is not sent to my home manager.

Normally, I would send it like this:

hmImports = [
  (import ./home.nix)

That does not work for some reason, and neither does writing it like inputs.nur.nixosModules.nur

Here’s the snippet from my firefox defaut.nix:

extensions = with pkgs.nur.repos.rycee.firefox-addons; [

It just returns with the error:

       error: attribute 'nur' missing

       at /nix/store/d0blvd3kna5i4a49h0c2g8fzr38793aj-source/settings/firefox/default.nix:8:27:

            8|         extensions = with pkgs.nur.repos.rycee.firefox-addons; [
             |                           ^
            9|             ublock-origin
       Did you mean one of nurl, nut, nux, pur or acr?