Examine source code of Flu Forest

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Flu Forest",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(68, 131, 18, 0.24)",
      "toolbar_text": "rgb(242, 243, 245)",
      "frame": "rgb(57, 77, 92)",
      "tab_background_text": "rgb(251, 251, 251)",
      "toolbar_field": "rgba(0, 0, 0, 0.2)",
      "toolbar_field_text": "rgb(242, 243, 245)",
      "tab_line": "rgba(25, 141, 124, 0.99)",
      "popup": "rgba(9, 62, 56, 0.91)",
      "popup_text": "rgb(242, 243, 245)",
      "button_background_active": "rgb(189, 117, 88)",
      "frame_inactive": "rgba(9, 62, 56, 0.48)",
      "icons_attention": "rgb(192, 87, 45)",
      "icons": "rgba(170, 248, 238, 0.8)",
      "ntp_background": "rgb(143, 176, 172)",
      "ntp_text": "rgb(9, 62, 56)",
      "popup_border": "rgba(25, 192, 168, 0.99)",
      "popup_highlight_text": "rgb(251, 251, 251)",
      "popup_highlight": "rgba(19, 93, 19, 0.8)",
      "sidebar_border": "rgba(25, 192, 168, 0.99)",
      "sidebar_highlight": "rgba(21, 132, 21, 0.8)",
      "sidebar_text": "rgb(251, 251, 251)",
      "sidebar": "rgb(9, 62, 56)",
      "tab_background_separator": "rgba(26, 132, 25, 0.8)",
      "tab_loading": "rgb(189, 117, 88)",
      "tab_text": "rgb(242, 243, 245)",
      "toolbar_bottom_separator": "rgba(12, 63, 11, 0.8)",
      "toolbar_field_border_focus": "rgba(26, 165, 26, 0.8)",
      "toolbar_field_border": "rgba(21, 132, 21, 0.8)",
      "toolbar_field_focus": "rgba(9, 62, 56, 0.48)",
      "toolbar_field_highlight_text": "rgb(251, 251, 251)",
      "toolbar_field_highlight": "rgba(26, 132, 25, 0.8)",
      "toolbar_field_separator": "rgba(25, 192, 168, 0.99)",
      "toolbar_field_text_focus": "rgb(223, 18, 132)",
      "toolbar_top_separator": "rgba(23, 118, 23, 0.8)",
      "toolbar_vertical_separator": "rgba(25, 192, 168, 0.8)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{07a35cd7-4253-4d2a-bdda-a37adc446ea9}"
    }
  }
}