Examine source code of Amazon Tracking Link

{
  "manifest_version": 3,
  "name": "Amazon Tracking Link",
  "description": "Amazon.co.jpの配送状況のトラッキングIDを配送業者の追跡ページのリンクにする拡張機能",
  "version": "1.0.4",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "default_locale": "ja",
  "homepage_url": "https://github.com/Midra429/amazon-tracking-link",
  "browser_specific_settings": {
    "gecko": {
      "id": "amazon-tracking-link@midra.me",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.amazon.co.jp/gp/your-account/ship-track?*",
        "https://www.amazon.co.jp/progress-tracker/package?*"
      ],
      "run_at": "document_end",
      "js": [
        "content-scripts/content.js"
      ]
    }
  ]
}