Examine source code of B3 FII Extension

{
  "manifest_version": 2,
  "name": "B3 FII Extension",
  "version": "1.0",
  "description": "Encontra os melhores FIIs com base em vários critérios.",
  "icons": {
    "48": "icons/icon48.png"
  },
  "browser_action": {
    "default_icon": "icons/icon48.png",
    "default_popup": "popup.html"
  },
  "permissions": [
    "https://www.b3.com.br/*"
  ],
  "content_security_policy": "script-src 'self' https://www.b3.com.br; object-src 'self'",
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{31ed4b26-9861-4c64-a76c-2719f68204d3}"
    }
  }
}