Examine source code of yellow HTML

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "yellow HTML",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(255, 255, 0)",
      "toolbar_text": "rgb(43, 42, 51)",
      "frame": "rgb(46, 46, 46)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(255, 255, 255, 0.66)",
      "toolbar_field_text": "rgb(43, 42, 51)",
      "tab_line": "rgb(43, 42, 51)",
      "popup": "rgb(255, 255, 251)",
      "popup_text": "rgb(43, 42, 51)",
      "tab_loading": "rgb(43, 42, 51)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a41c1016-fba1-4e78-92b0-df7e181cfdb2}"
    }
  }
}