Examine source code of My Contacts Cloud

{
  "manifest_version": 2,
  "name": "My Contacts Cloud",
  "version": "1.2.0",
  "description": "__MSG_extensionDescription__",
  "permissions": [
    "tabs"
  ],
  "browser_action": {
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    },
    "default_title": "My Contacts Cloud"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "{69472445-2faf-41ea-9ed4-10e2f47acf0e}"
    }
  }
}