Examine source code of TAXFree

{
  "manifest_version": 2,
  "name": "TAXFree",
  "version": "0.4.0.5",
  "author": "MDaniel",
  "description": "Discount the TAX/VAT applied to all products + Quick identification of Amazon products with shipping restrictions.",
  "homepage_url": "https://github.com/MDaniel592/TaxFree",
  "default_locale": "en",
  "icons": {
    "32": "img/taxfree_32x32.png",
    "64": "img/taxfree_64x64.png",
    "128": "img/taxfree_128x128.png",
    "256": "img/taxfree_256x256.png",
    "512": "img/taxfree_512x512.png"
  },
  "browser_action": {
    "browser_style": true,
    "default_icon": {
      "32": "img/taxfree_32x32.png",
      "64": "img/taxfree_64x64.png",
      "128": "img/taxfree_128x128.png",
      "256": "img/taxfree_256x256.png",
      "512": "img/taxfree_512x512.png"
    },
    "default_title": "TAXFree Add-on",
    "default_popup": "html/popup.html"
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "background": {
    "scripts": [
      "external_js/browser-polyfill.js",
      "external_js/jquery-3.6.1.min.js",
      "core_js/storage.js",
      "background/background.js"
    ]
  },
  "content_scripts": [
    {
      "all_frames": true,
      "matches": [
        "https://www.amazon.es/*",
        "https://www.amazon.co.uk/*",
        "https://www.amazon.fr/*",
        "https://www.amazon.de/*",
        "https://www.amazon.it/*"
      ],
      "css": [
        "css/loader.css",
        "css/products.css"
      ],
      "js": [
        "external_js/browser-polyfill.js",
        "content_scripts/taxfree.js",
        "content_scripts/search.js"
      ],
      "run_at": "document_start"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{20c907e0-d3a3-4621-bb73-b4ccf9e40158}"
    }
  }
}