Examine source code of Light yet Dark

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Dark Trees",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(230, 225, 194, 0.64)",
      "toolbar_text": "rgba(0, 0, 0, 0.65)",
      "frame": "rgb(230, 225, 194)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgba(0, 0, 0, 0.85)",
      "tab_line": "rgba(0, 0, 0, 0.42)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(0, 0, 0)",
      "tab_loading": "rgba(0, 0, 0, 0.42)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f5de73e3-c6ff-4107-96a1-6f723f62de6c}"
    }
  }
}