Examine source code of Thundering Dark Sky

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Thundering Dark Theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(47, 47, 47)",
      "toolbar_text": "rgb(229, 229, 229)",
      "frame": "rgb(32, 32, 32)",
      "tab_background_text": "rgb(229, 229, 229)",
      "toolbar_field": "rgb(66, 66, 66)",
      "toolbar_field_text": "rgb(229, 229, 229)",
      "tab_line": "rgb(93, 93, 93)",
      "popup": "rgb(18, 18, 18)",
      "popup_text": "rgb(229, 229, 229)",
      "tab_loading": "rgb(93, 93, 93)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c4354599-9bd8-456b-9a28-3189dce42c41}"
    }
  }
}