TE

Lists the transfer codings a client accepts and whether it accepts trailer fields.

TE is hop-by-hop and applies to transfer codings such as trailers, not content codings like gzip. A proxy must not forward it blindly.

httpheaderframingproxysecurity

Reference (http)

TE: trailers

TE is hop-by-hop and applies to transfer codings such as trailers, not content codings like gzip. A proxy must not forward it blindly.

Common mistakes

Confusing TE with Accept-Encoding or forwarding hop-by-hop fields across a proxy boundary.

IANA registry: http-fields/field-names

Sources