Examine source code of Silver Shadow

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Sombra Prateada",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(8, 8, 8)",
      "toolbar_text": "rgb(242, 242, 242)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(161, 161, 167)",
      "toolbar_field": "rgb(0, 0, 0)",
      "toolbar_field_text": "rgb(145, 145, 151)",
      "tab_line": "rgba(126, 134, 134, 0.88)",
      "popup": "rgb(52, 53, 54)",
      "popup_text": "rgb(140, 140, 140)",
      "button_background_active": "rgb(116, 116, 131)",
      "frame_inactive": "rgb(0, 0, 0)",
      "icons_attention": "rgb(255, 255, 255)",
      "icons": "rgb(137, 137, 142)",
      "ntp_background": "rgb(0, 0, 0)",
      "ntp_text": "rgb(14, 14, 15)",
      "popup_border": "rgb(94, 94, 94)",
      "popup_highlight": "rgb(13, 13, 33)",
      "tab_loading": "rgb(86, 86, 86)",
      "tab_selected": "rgb(19, 19, 19)",
      "toolbar_bottom_separator": "rgb(0, 0, 0)",
      "toolbar_field_border": "rgb(74, 74, 74)",
      "toolbar_field_highlight_text": "rgb(0, 0, 0)",
      "toolbar_top_separator": "rgb(15, 15, 15)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{450a824e-a273-412a-85fd-99805a137517}"
    }
  }
}