User Agent: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
The server is running: Apache

Predefined variables in PHP, such as $_SERVER, are built-in variables that hold information about the server, request, and environment. They are automatically available for use, providing details like server IP address and user agent.