> https://github.com/python-trio/trio/blob/master/trio/_highlevel_open_tcp_listeners.py

Extract:

# A large backlog can also use a bit more kernel memory, but this seems fairly
# negligible these days.

That's the main question here. Python is used on various platforms for various use cases.

Extract of the current C code:

    /* We try to choose a default backlog high enough to avoid connection drops
     * for common workloads, yet not too high to limit resource usage. */
    int backlog = Py_MIN(SOMAXCONN, 128);

Maybe the status quo is just fine and this issue should be closed. It's trivial to override the default. This issue is stricted to the *default* value.