Examine source code of UnderWater

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "UnderWater",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat-x"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 49, 40, 0.3)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(36, 12, 55)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(2, 105, 111)",
      "popup": "rgb(2, 164, 159)",
      "popup_text": "rgb(0, 0, 0)",
      "button_background_active": "rgb(2, 105, 111)",
      "button_background_hover": "rgb(4, 158, 104)",
      "icons_attention": "rgb(0, 102, 172)",
      "icons": "rgb(0, 200, 255)",
      "ntp_background": "rgb(0, 85, 121)",
      "ntp_text": "rgb(0, 0, 0)",
      "sidebar_text": "rgb(0, 0, 0)",
      "tab_background_separator": "rgb(174, 113, 0)",
      "tab_text": "rgb(255, 255, 255)",
      "toolbar_field_highlight": "rgb(0, 115, 179)",
      "toolbar_field_separator": "rgb(3, 55, 132)",
      "toolbar_top_separator": "rgb(1, 63, 135)",
      "toolbar_vertical_separator": "rgb(0, 41, 192)",
      "tab_loading": "rgb(2, 105, 111)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{3860ad60-a388-449d-8f37-53dd7be9e4ae}"
    }
  }
}