anchor.diff:  { fetchurl, lib, stdenv, squashfsTools, xorg, alsaLib, makeWrapper, openssl, freetype
  -, glib, pango, cairo, atk, gdk-pixbuf, gtk2, cups, nspr, nss, libpng, libnotify
  +, glib, pango, cairo, atk, gdk-pixbuf, gtk3, cups, nspr, nss, libpng, libnotify
   , libgcrypt, systemd, fontconfig, dbus, expat, ffmpeg_3, curl, zlib, gnome3
  -, at-spi2-atk, at-spi2-core, libpulseaudio, libdrm, mesa
  +, at-spi2-atk, at-spi2-core, libpulseaudio, libdrm, mesa, libxkbcommon
   }:
   
   let
  
positive.code:   # If an update breaks things, one of those might have valuable info:
    # https://aur.archlinux.org/packages/spotify/
    # https://community.spotify.com/t5/Desktop-Linux
    version = "1.1.46.916.g416cacf1";
    # To get the latest stable revision:
    # curl -H 'X-Ubuntu-Series: 16' 'https://api.snapcraft.io/api/v1/snaps/details/spotify?channel=stable' | jq '.download_url,.version,.last_updated'
    # To get general information:
    # curl -H 'Snap-Device-Series: 16' 'https://api.snapcraft.io/v2/snaps/info/spotify' | jq '.'
    # More examples of api usage:
    # https://github.com/canonical-websites/snapcraft.io/blob/master/webapp/publisher/snaps/views.py
    rev = "43";
  
    deps = [
      alsaLib
  
negative.code:   # https://community.spotify.com/t5/Desktop-Linux/Redistribute-Spotify-on-Linux-Distributions/td-p/1695334
    src = fetchurl {
      url = "https://api.snapcraft.io/api/v1/snaps/download/pOBIoZ2LrCB3rDohMxoYGnbN14EHOgD7_${rev}.snap";
      sha512 = "5d61a2d5b26be651620ab5d18d3a204d8d7b09dcec8a733ddc176c44cb43e9176c4350933ebe4498b065ba219113f3226c13bea9659da738fe635f41d01db303";
    };
  
    nativeBuildInputs = [ makeWrapper squashfsTools ];
  
    dontStrip = true;
    dontPatchELF = true;
  