Examine source code of Print to PDF

{
  "version": "0.1.0",
  "manifest_version": 2,
  "name": "Print to PDF",
  "short_name": "printtopdf",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "applications": {
    "gecko": {
      "strict_min_version": "56.0",
      "id": "{714cebe7-c0ea-4972-a044-27d605171f0f}"
    }
  },
  "homepage_url": "http://mybrowseraddon.com/print-to-pdf.html",
  "description": "Easily print any page to PDF with just one click!",
  "options_ui": {
    "chrome_style": true,
    "page": "data/options/options.html"
  },
  "permissions": [
    "tabs",
    "storage",
    "<all_urls>",
    "contextMenus"
  ],
  "browser_action": {
    "default_title": "Print to PDF",
    "default_icon": {
      "16": "data/icons/16.png",
      "32": "data/icons/32.png",
      "48": "data/icons/48.png",
      "64": "data/icons/64.png"
    }
  },
  "icons": {
    "16": "data/icons/16.png",
    "32": "data/icons/32.png",
    "48": "data/icons/48.png",
    "64": "data/icons/64.png",
    "128": "data/icons/128.png"
  }
}