Examine source code of Caixa Postal - Envios de Mensagens

{
  "manifest_version": 3,
  "name": "Caixa Postal - Envios de Mensagens",
  "version": "2.3",
  "description": "Extensão para envios de mensagens para Caixa Postal Gov.br",
  "icons": {
    "16": "img/favicon-16x16.png",
    "32": "img/favicon-32x32.png",
    "48": "img/favicon-48x48.png",
    "128": "img/favicon-128x128.png"
  },
  "action": {
    "default_icon": "img/logo192.png",
    "default_popup": "caixapostal.html"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "activeTab",
    "scripting"
  ],
  "host_permissions": [
    "https://*.gov.br/*"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@cxpostalplus-cgini",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://api-orgaos-cxpostal.estaleiro.serpro.gov.br/swagger/cxplus"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "caixapostal.html",
        "styles.css",
        "fonts/*",
        "js/*.js",
        "img/*"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ]
}