Examine source code of Winter spruces

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Winter spruces",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(4, 7, 31, 0.5)",
      "toolbar_text": "rgb(228, 222, 255)",
      "frame": "rgb(207, 194, 227)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(4, 7, 31)",
      "tab_line": "rgb(255, 217, 201)",
      "popup": "rgb(228, 222, 255)",
      "popup_text": "rgb(4, 7, 31)",
      "tab_loading": "rgb(255, 217, 201)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{685642a6-7733-4e06-84c7-8f6c45adf762}"
    }
  }
}