Which HTTP header field is usually used in forensics to identify the type of browser used?

The Accept-Language header conveys the human language preferences of the client user rather than any information about the browser type or version.

The User-Agent header is included in every HTTP request and carries a standardized string describing the client browser name, version, rendering engine, and underlying operating system. Forensic analysts extract this field from web server access logs or packet captures to attribute web activity to specific browser versions or to detect anomalous clients such as malware using spoofed or unusual agent strings. It is the definitive HTTP header for browser fingerprinting and client software identification.

The Referer header contains the URL of the page that initiated the current request, providing navigational context but no data identifying the browser software itself.

The Host header specifies the target server domain name to support virtual hosting and contains no information about the requesting client browser.