You probably reached this page by being redirected from The User Agent Redirection Test Page.
Note: the server does not have particularly good user agent detection so it will not work for all mobile user agents. It is deliberately buggy.
Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
Based on the user agent you supplied. The server thought you were using a mobile.
Note: This is a pretty old fashioned way of handling mobile devices. Most websites now are responsive, and will work on both desktop and mobile, and so no separate mobile pages, or subdomain would be used.