I'm wondering whether this should have a comment inline with the code as to the expectation for the variable. Thoughts @dandhlee ?

For java we have https://github.com/GoogleCloudPlatform/java-docs-samples/blob/HEAD/appengine-java11/http-server/src/main/java/com/example/appengine/Main.java#L27-L28; the code is slightly different in it has a fallback to 8080 if the variable isn't defined, but it feels helpful to me to define.

I think it's better to leave this one as-is, and add comments elsewhere. This code seems to show up embedded in this doc: https://cloud.google.com/appengine/docs/standard/python3/runtime.md, which I think comment there would help more than an inline comment here and then the doc looking slightly weird.

If this file had a lot more code I think it'd be worth having comments, but it's such a short file already :/

Thanks so much @dandhlee :)