Examine source code of Email Reply Generator

{
  "name": "Email Reply Generator",
  "description": "AI-powered email reply generator",
  "version": "1.0.1",
  "manifest_version": 3,
  "browser_specific_settings": {
    "gecko": {
      "id": "email-reply-generator@example.com"
    }
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "host_permissions": [
    "https://emailreplygen-production.up.railway.app/api/email/generate",
    "*://mail.google.com/*"
  ],
  "content_scripts": [
    {
      "js": [
        "content.js"
      ],
      "matches": [
        "*://mail.google.com/*"
      ],
      "css": [
        "content.css"
      ],
      "run_at": "document_end"
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "icons/*"
      ],
      "matches": [
        "*://mail.google.com/*"
      ]
    }
  ],
  "action": {
    "default_title": "Email Reply Generator",
    "default_icon": "extension_icon.jpg"
  }
}