Examine source code of Large Integer Addition

{
  "manifest_version": 2,
  "name": "Large Integer Addition",
  "version": "1.0",
  "description": "A Mozilla Addon to calculate the sum of large integers",
  "icons": {
    "48": "icon.png"
  },
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9dbc4637-502d-4ab9-ac77-a9b7b0c89ddf}"
    }
  }
}