Examine source code of Four leaves

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Four leaves",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat-x"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 127, 36)",
      "toolbar_text": "rgb(255, 183, 0)",
      "frame": "rgb(0, 185, 52)",
      "tab_background_text": "rgb(62, 26, 0)",
      "toolbar_field": "rgb(219, 255, 190)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(255, 245, 0)",
      "popup": "rgb(184, 255, 127)",
      "popup_text": "rgb(0, 70, 20)",
      "tab_loading": "rgb(255, 245, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c266a2ea-0cb0-486d-a1a5-038ca1226b3c}"
    }
  }
}