The header of HTTP requests contains a User-Agent field.
It is used by browsers to identify themselves and give information about their version.
The server can adapt the page to an older Internet Explorer or a newer Firefox browser.

Curl v7.68.0 uses 'curl/7.68.0' as the User-Agent. It is possible to set the User-Agent value with the -A option.

curl -A 'MyAgent' http://localhost:8001