Examine source code of Lurnby

{
  "manifest_version": 2,
  "name": "Lurnby",
  "version": "2.21",
  "description": "Sends the current url to your Lurnby account for reading",
  "browser_specific_settings": {
    "gecko": {
      "id": "learnbetter@test.org"
    }
  },
  "background": {
    "scripts": [
      "background/authorize.js",
      "background/userinfo.js",
      "background/main.js"
    ]
  },
  "icons": {
    "48": "icons/rrbetterface-48.png",
    "96": "icons/rrbetterface-96.png"
  },
  "permissions": [
    "tabs",
    "identity",
    "notifications",
    "cookies",
    "*://www.googleapis.com/*",
    "*://localhost:5000/*",
    "https://app.lurnby.com/*",
    "*://accounts.google.com/*",
    "*://dd826413-46f4-3c4d-87be-c8d5526c4766/*",
    "https://www.lurnby.com/*"
  ],
  "options_ui": {
    "page": "options/options.html"
  },
  "browser_action": {
    "default_icon": "icons/rrbetterface-32.png",
    "default_title": "Lurnby Extension",
    "default_popup": "popup/login.html"
  },
  "web_accessible_resources": [
    "icons/*.png"
  ]
}