Examine source code of Manga Tracker

{
  "manifest_version": 3,
  "name": "Manga Tracker",
  "version": "1.2",
  "author": "Murcis_Luis",
  "description": "Guarda automáticamente la información del manga y la posición de scroll",
  "permissions": [
    "storage",
    "tabs"
  ],
  "icons": {
    "16": "images/ico-16.png",
    "32": "images/ico-32.png",
    "64": "images/ico-64.png",
    "128": "images/ico-128.png"
  },
  "action": {
    "default_popup": "/popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "https://zonaolympus.com/*",
        "https://www.leercapitulo.co/*",
        "https://taurusmanga.com/*"
      ],
      "js": [
        "browser-polyfill.min.js",
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "header.html",
        "headerLoader.js",
        "styles.css"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "default_locale": "en",
  "browser_specific_settings": {
    "gecko": {
      "id": "murcisluis@mangatracker.com"
    }
  }
}