A User-Agent (UA) is an alphanumeric string passed in HTTP headers that identifies the software and hardware of the device making a web request, allowing for decisions ranging from simple segmentation to complex content adaptation and device targeting, with additional data such as carrier ID and screen resolution available when mapped to real-time data.
Listeners may have multiple user agents if they change devices or update their player. Ensuring that third parties can identify multiple user agents associated with single users helps prevent traffic from being deemed fraudulent, which can lead to geolocation issues and reporting discrepancies.