Examine source code of Firma con token test

{
  "description": "Extensión que permite firmar digitalmente con token, desde su navegador",
  "manifest_version": 3,
  "name": "Firma con token",
  "version": "3.2.2",
  "icons": {
    "128": "ico36.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "firma.con.token@ssia.gde.gob.ar"
    }
  },
  "background": {
    "scripts": [
      "main.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "all_frames": true,
      "js": [
        "content-script.js"
      ],
      "run_at": "document_end"
    }
  ],
  "permissions": [
    "nativeMessaging",
    "activeTab"
  ]
}