1.8 Vendor-Extensible Fields
HTTP Encapsulation of SSTP protocol uses and specifies the following vendor extensible fields as specified in sections 2.2.1.2.3 and 2.2.1.3.2 respectively.
User-Agent product token value: "Mozilla/4.0 (compatible; MSIE 5.5; Win32)"
HTTP Response Server header server-product-name token value: "Groove-Relay/12.0" or "Groove‑Relay/14.0"
HTTP Encapsulation of SSTP protocol supports HTTP extensible headers and header-entity fields as specified in HTTP 1.0 [RFC1945] sections 5.2, 6.2 and 7.1.