Examine source code of Export Web to PDF

{
  "manifest_version": 2,
  "name": "Export Web to PDF",
  "description": "Exports the current webpage when you click the icon",
  "version": "2.0",
  "icons": {
    "170": "icon.png"
  },
  "permissions": [
    "tabs",
    "downloads.open"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "170": "icon.png"
    },
    "default_title": "Export to PDF"
  }
}