Examine source code of Silent Auto Print

{
  "manifest_version": 2,
  "name": "Silent Auto Print",
  "version": "1.4.4",
  "description": "Impresión silenciosa con jsPrintSetup: impresora fija, tamaño, bandeja, márgenes, orientación y copias. Incluye perfil Ticket.",
  "icons": {
    "48": "icons/icon-48.png",
    "96": "icons/icon-96.png"
  },
  "browser_action": {
    "default_title": "Silent Auto Print",
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/icon-48.png"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "storage",
    "activeTab",
    "tabs",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "silent-auto-print@miempresa.local",
      "strict_min_version": "91.0"
    }
  }
}