Examine source code of Topography Map

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Topography",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(90, 90, 90)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(172, 172, 172)",
      "frame_inactive": "rgb(117, 117, 117)",
      "icons": "rgb(128, 128, 128)",
      "ntp_text": "rgb(203, 203, 203)",
      "popup_highlight_text": "rgb(241, 241, 241)",
      "sidebar_border": "rgb(255, 255, 255)",
      "sidebar_highlight": "rgb(255, 255, 255)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c63c6869-963e-43e3-bb0b-e93d2c194468}"
    }
  }
}