This version is used with pgx v4. In pgx v5 it is part of the https://github.com/jackc/pgx repository.
Package pgproto3 is a encoder and decoder of the PostgreSQL wire protocol version 3.
pgproto3 can be used as a foundation for PostgreSQL drivers, proxies, mock servers, load balancers and more.
See example/pgfortune for a playful example of a fake PostgreSQL server.
Extracted from original implementation in https://github.com/jackc/pgx.