nixos-combined-flake/modules/nixvim/plugins/undotree.nix

{
  plugins.undotree.enable = true;
  keymaps = [
    {
      key = "<leader>u";
      action = "<cmd>UndotreeToggle<CR>";
      options = {
        silent = true;
        desc = "[undotree] Toggle";
      };
    }
  ];
}