Migration guide for existing subpar users now that it is "unmaintained and considered deprecated"?

[rogerhub]

Hello. I noticed that the README says:

This project is unmaintained and considered deprecated.
Historically, subpar was the only way to produce a deployable Python artifact in Bazel.
This is no longer true; --build_python_zip and the python_zip_file output_group allows you to create executable Python zip artifacts with the standard py_binary rule.
rules_docker can also be used to build container images that launch py_binary.

Is there a migration guide for current users of subpar to help them transition to python_zip_file? Some specific questions I have are:

• How do I produce a python binary which is self-executing? It seems that subpar can do this because it adds #!/usr/bin/env python3 but python_zip_file isn't doing this for me.
• Is there any replacement for zip_safe = False?