HTTP/2 (RFC 9113)

1. Starting HTTP/2

   Connection preface, ALPN negotiation and prior-knowledge h2c.

2. Frame format

   The 9-octet frame header, frame types, flags and stream identifiers.

3. Streams and multiplexing

   Stream identifiers, concurrent streams and the multiplexing model.

4. Stream states

   Idle, open, half-closed, reserved and closed stream state machine.

5. Flow control

   Per-stream and connection WINDOW_UPDATE flow control.

6. Frame definitions

   DATA, HEADERS, RST_STREAM, SETTINGS, PUSH_PROMISE, PING, GOAWAY and CONTINUATION frames.

7. Error codes

   Connection and stream error codes such as PROTOCOL_ERROR and REFUSED_STREAM.

8. HTTP message exchanges

   Pseudo-header fields, request/response framing and server push semantics.

9. TLS features and security

   TLS 1.2+ requirements, cipher suite restrictions and ALPN.

10. HPACK header compression

    Static and dynamic tables, indexing and Huffman coding for header compression.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.