Examine source code of Background Blur

{
  "manifest_version": 2,
  "version": "1.4",
  "name": "Background Blur",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(27, 27, 27)",
      "toolbar_text": "rgb(226, 226, 226)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(226, 226, 226)",
      "toolbar_field": "rgb(19, 19, 19)",
      "toolbar_field_text": "rgb(226, 226, 226)",
      "tab_line": "rgb(27, 27, 27)",
      "popup": "rgb(27, 27, 27)",
      "popup_text": "rgb(226, 226, 226)",
      "tab_loading": "rgb(27, 27, 27)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8fa57957-0115-4b5a-88c5-17e83bb2368d}"
    }
  }
}