Examine source code of Spotify Premium Theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Death Star theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(133, 151, 203)",
      "toolbar_text": "rgb(12, 4, 14)",
      "frame": "rgb(255, 255, 255)",
      "tab_background_text": "rgb(185, 17, 223)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(185, 17, 223)",
      "tab_line": "rgb(185, 17, 223)",
      "popup": "rgb(243, 244, 247)",
      "popup_text": "rgb(185, 17, 223)",
      "tab_loading": "rgb(185, 17, 223)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6916b86e-10fb-424e-b0da-128f27a2fced}"
    }
  }
}