What happened:
Small flaw in conformance test container echo-basic. It always runs the h2c server, even if that isn't being tested in the echo-basic container.

What you expected to happen:
Only run the h2c server if there is an H2C_PORT configured in the environment.

How to reproduce it (as minimally and precisely as possible):
Start the echo-basic container (run any test that makes an http request). Look at the logs of the pod containing echo-basic container, and you will see the log:

Starting server, listening on port 3001 (h2c)

Anything else we need to know?:
The same story goes for the http server, but it is almost always used by tests, whereas h2c server is rarely used.
The https server is only run if TLS_SERVER_CERT or TLS_SERVER_PRIVKEY are available in the environment.
Good first issue in the conformance area, get to learn about echo-basic and how it works with the conformance tests and yaml.