Examine source code of Check This Place

{
  "name": "Check This Place",
  "description": "Create posts about locations and places and share them in Facebook, Google+ and Twitter.",
  "author": "Pantelis Rodis",
  "version": "1.2resigned1",
  "manifest_version": 2,
  "background": {
    "scripts": [
      "open.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "16": "icons/logo-16.png",
      "32": "icons/logo-32.png",
      "48": "icons/logo-48.png",
      "50": "icons/logo-50.png",
      "60": "icons/logo-60.png",
      "72": "icons/logo-72.png",
      "96": "icons/logo-96.png",
      "120": "icons/logo-120.png",
      "128": "icons/logo-128.png",
      "144": "icons/logo-144.png",
      "168": "icons/logo-168.png",
      "192": "icons/logo-192.png",
      "512": "icons/logo-512.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{29a7d3a6-c0da-40bb-a004-e74302616903}"
    }
  }
}