jstest/sharding/libs/proxy_protocol_server.py imports a module from the "proxyprotocol" Python package, but the string "proxyprotocol" does not appear anywhere else in our source code.

That's because the package is installed from the internet for test, and it's called "proxy-protocol" with a hyphen.

It would be helpful for newcomers if this fact were mentioned in a comment in proxy_protocol_server.py.