HTTP 2.0 marks the end of an era
As James Snell points out, apart from all the new features like multiplexing and flow control, the biggest visible change in the HTTP 2.0 spec is that it is now a binary protocol, not a text-based one like HTTP 1.1. See his post for an example of the binary stream that represents what would have been a “GET” request in 1.1.
With 1.1, you could literally read off what was on the wire and make sense of it, because it was just plain text. Now you’ll see a stream of opaque bytes.
To me, this marks the end of an era. The early web was designed to be legible to humans, at the expense of some machine resources. Plain text was surely not a compact representation, but it was the simplest one. Chatter between machines and humans was as important as chatter among machines. The web has now reached the maturity and scale that the cost equation has flipped.