Examine source code of Gerar CPF

{
  "name": "Gerar CPF",
  "version": "1.1",
  "description": "Gerador de CPF",
  "manifest_version": 2,
  "icons": {
    "16": "images/icon16.png",
    "24": "images/icon24.png",
    "32": "images/icon32.png",
    "64": "images/icon64.png",
    "128": "images/icon128.png"
  },
  "browser_action": {
    "name": "Clique para gerar seu CPF"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab"
  ]
}