Examine source code of SEO ToolBox Pro

{
  "manifest_version": 2,
  "name": "SEO ToolBox Pro",
  "version": "4.1",
  "permissions": [
    "activeTab",
    "tabs",
    "downloads",
    "<all_urls>",
    "https://chromeuxreport.googleapis.com/*"
  ],
  "icons": {
    "16": "/icons/RedEx16-8.png",
    "48": "/icons/RedEx48-8.png",
    "128": "/icons/RedEx128-8.png"
  },
  "browser_action": {
    "default_popup": "index.html",
    "default_title": "React SEO Extension"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "contentScript.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{f720c549-c028-470c-8fe0-2b12b6e63ea8}"
    }
  }
}