Examine source code of Halloween-y

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Halloween-y",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(31, 15, 48)",
      "toolbar_text": "rgb(251, 122, 24)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(189, 125, 242)",
      "toolbar_field": "rgba(255, 136, 47, 0.67)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(251, 122, 24)",
      "popup": "rgb(23, 0, 43)",
      "popup_text": "rgb(251, 122, 24)",
      "button_background_active": "rgba(255, 118, 0, 0.76)",
      "button_background_hover": "rgba(147, 179, 178, 0.47)",
      "frame_inactive": "rgb(127, 255, 122)",
      "icons_attention": "rgba(255, 110, 0, 0.76)",
      "icons": "rgb(191, 131, 240)",
      "popup_border": "rgb(191, 131, 240)",
      "popup_highlight_text": "rgb(255, 255, 255)",
      "popup_highlight": "rgba(0, 0, 0, 0.76)",
      "tab_background_separator": "rgb(248, 112, 140)",
      "tab_loading": "rgb(217, 82, 82)",
      "tab_selected": "rgba(138, 66, 196, 0.65)",
      "tab_text": "rgb(251, 122, 24)",
      "toolbar_bottom_separator": "rgba(255, 118, 0, 0.76)",
      "toolbar_field_border_focus": "rgb(248, 112, 140)",
      "toolbar_field_border": "rgb(131, 60, 189)",
      "toolbar_field_focus": "rgb(242, 242, 242)",
      "toolbar_field_highlight_text": "rgb(140, 0, 255)",
      "toolbar_field_highlight": "rgba(255, 118, 0, 0.37)",
      "toolbar_field_text_focus": "rgb(140, 0, 255)",
      "toolbar_top_separator": "rgba(255, 118, 0, 0.76)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{8d8f30d8-7833-42aa-8aa9-d18d5a82cdca}"
    }
  }
}