Examine source code of IO Games

{
  "manifest_version": 2,
  "name": "IO Games",
  "description": "Play all your favourite .io games with this great io games addon.",
  "version": "0.2resigned1",
  "homepage_url": "http://iogames.land",
  "applications": {
    "gecko": {
      "id": "iogames@iogames.land"
    }
  },
  "browser_action": {
    "default_icon": "/images/logo48.png",
    "default_popup": "popup.html"
  },
  "icons": {
    "16": "/images/logo16.png",
    "48": "/images/logo48.png",
    "128": "/images/logo128.png",
    "256": "/images/logo256.png"
  },
  "permissions": [
    "https://*/*",
    "http://*/*",
    "storage"
  ],
  "background": {
    "scripts": [
      "/js/jquery-3.2.1.min.js",
      "/js/isotope.js",
      "/js/custom-masonry.js",
      "app.js"
    ]
  }
}