UA-* headers

HTTP The Definitive Guide

Request headers are headers that make sense only in a request message. They give information about
who or what is sending the request, where the request originated, or what the preferences and
capabilities of the client are. Servers can use the information the request headers give them about the
client to try to give the client a better response. Table 3-13 lists the request informational headers.
Table 3-13. Request informational headers