TE request header specifies the transfer encodings the user agent is willing to accept. (you could informally call it
Accept-Transfer-Encoding, which would be more intuitive).
See also the
Transfer-Encoding response header for more details on transfer encodings. Note that
chunked is always acceptable for HTTP/1.1 recipients and you don't have to specify
"chunked" using the
TE header. However, it is useful for setting if the client is accepting trailer fields in a chunked transfer coding using the "trailers" value.