Examine source code of Auto 2FA

{
  "manifest_version": 2,
  "name": "Auto 2FA",
  "description": "Login through Duo Mobile in your browser",
  "version": "1.6.5",
  "icons": {
    "16": "icon/16.png",
    "32": "icon/32.png",
    "48": "icon/48.png",
    "96": "icon/96.png",
    "128": "icon/128.png"
  },
  "permissions": [
    "storage",
    "activeTab",
    "scripting",
    "https://*.duosecurity.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Auto 2FA",
    "default_popup": "popup.html"
  },
  "options_ui": {
    "open_in_tab": true,
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.duosecurity.com/frame/*/auth/prompt*",
        "https://*.duosecurity.com/frame/prompt*"
      ],
      "js": [
        "content-scripts/login.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{dc560796-6096-490d-96a7-e0c6ceef2ac2}"
    }
  }
}