Examine source code of Typify

{
  "manifest_version": 2,
  "name": "Typify",
  "version": "2.0",
  "permissions": [
    "tabs",
    "activeTab",
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "48": "icons/icon.png",
      "96": "icons/icon@2x.png"
    },
    "default_title": "Typify this page"
  }
}