Examine source code of eBay Total Cost Display

{
  "manifest_version": 3,
  "name": "eBay Total Cost Display",
  "version": "1.1.0",
  "description": "Displays the total cost (item price + shipping) for eBay listings, including single prices and price ranges.",
  "author": "Robert Carballo",
  "icons": {
    "48": "icon48.png",
    "96": "icon96.png"
  },
  "permissions": [
    "activeTab"
  ],
  "host_permissions": [
    "*://*.ebay.com/*",
    "*://*.ebay.co.uk/*",
    "*://*.ebay.co.jp/*"
  ],
  "content_scripts": [
    {
      "matches": [
        "*://*.ebay.com/*",
        "*://*.ebay.co.uk/*",
        "*://*.ebay.co.jp/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{8a218a80-2468-46b2-b500-72f98fddf506}"
    }
  }
}