Examine source code of Star Filter for Amazon

{
  "manifest_version": 3,
  "name": "Star Filter for Amazon",
  "version": "1.0.0",
  "description": "Filter Amazon search results by star rating (4.5+, 4.6+, up to 5.0 stars). Not affiliated with Amazon.",
  "author": "JuanTan",
  "icons": {
    "48": "icons/icon.svg",
    "96": "icons/icon.svg"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "5omjkni8n@mozmail.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "storage"
  ],
  "action": {
    "default_title": "Star Filter for Amazon",
    "default_popup": "popup/popup.html",
    "default_icon": {
      "48": "icons/icon.svg",
      "96": "icons/icon.svg"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.amazon.com/*",
        "*://*.amazon.co.uk/*",
        "*://*.amazon.ca/*",
        "*://*.amazon.de/*",
        "*://*.amazon.fr/*",
        "*://*.amazon.es/*",
        "*://*.amazon.it/*",
        "*://*.amazon.com.au/*",
        "*://*.amazon.co.jp/*",
        "*://*.amazon.in/*",
        "*://*.amazon.com.mx/*",
        "*://*.amazon.com.br/*",
        "*://*.amazon.nl/*",
        "*://*.amazon.se/*"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ]
}