Examine source code of ShoppyCat

{
  "manifest_version": 3,
  "name": "ShoppyCat",
  "version": "1.3.0",
  "description": "Save items from Amazon, AliExpress, Temu, SHEIN, and Etsy to your ShoppyCat list, and see what your friends are buying.",
  "browser_specific_settings": {
    "gecko": {
      "id": "shoppycat@shoppycat.org",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "host_permissions": [
    "https://www.amazon.com/*",
    "https://www.amazon.co.uk/*",
    "https://www.amazon.de/*",
    "https://www.amazon.fr/*",
    "https://www.amazon.co.jp/*",
    "https://www.amazon.ca/*",
    "https://www.amazon.com.au/*",
    "https://*.aliexpress.com/*",
    "https://*.aliexpress.us/*",
    "https://www.shein.com/*",
    "https://us.shein.com/*",
    "https://www.temu.com/*",
    "https://www.etsy.com/*",
    "https://www.shoppycat.org/*"
  ],
  "background": {
    "scripts": [
      "shared/constants.js",
      "shared/api_client.js",
      "background/background.js"
    ]
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.amazon.com/*",
        "https://www.amazon.co.uk/*",
        "https://www.amazon.de/*",
        "https://www.amazon.fr/*",
        "https://www.amazon.co.jp/*",
        "https://www.amazon.ca/*",
        "https://www.amazon.com.au/*",
        "https://*.aliexpress.com/*",
        "https://*.aliexpress.us/*",
        "https://www.shein.com/*",
        "https://us.shein.com/*",
        "https://www.temu.com/*",
        "https://www.etsy.com/*"
      ],
      "js": [
        "shared/constants.js",
        "content_scripts/item_extractor.js",
        "content_scripts/checkout_detector.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "action": {
    "default_popup": "popup/popup.html",
    "default_title": "ShoppyCat",
    "default_icon": {
      "16": "icons/icon16.png",
      "48": "icons/icon48.png",
      "128": "icons/icon128.png"
    }
  },
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  }
}