Examine source code of Weed Background

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Weed",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(21, 26, 15)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(40, 40, 40)",
      "tab_background_text": "rgb(201, 245, 133)",
      "toolbar_field": "rgb(102, 104, 102)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(34, 93, 6)",
      "popup": "rgb(30, 30, 30)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(34, 93, 6)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{6b77f797-be2f-438e-9f3d-8a408b8f68dd}"
    }
  }
}