http://www.rfc-editor.org/rfc/rfc8164.txt
RFC 8164: Opportunistic Security for HTTP/2, M. Nottingham, M. Thomson2017-05-01T23:00:00-00:00This document describes how "http" URIs can be accessed using Transport Layer Security (TLS) and HTTP/2 to mitigate pervasive monitoring attacks. This mechanism not a replacement for "https" URIs; it is vulnerable to active attacks.