Serhiy Storchaka asked:
https://github.com/python/cpython/pull/18025#issuecomment-575645748

"""
What is a benefit of deprecating it?

This module is a high-level interface to several functions in the binascii module. This is all macOS specific stuff, so you need to ask macOS experts. If this encoding no longer used in macOS, its support can be removed, with deprecating first. If there are no plans to remove, there is no reason to deprecate.
"""

The intent is to reduce the size of the standard library to reduce the maintenance burden of Python in general. The final goal is to remove the module. But that's a first step to check if there is still any user around. We should deprecate it for at least one cycle.

I understood that binhex4 and hexbin4 standards were used on Mac OS 9 but are no longer used on macOS, nor used anywhere else. See my first message.

Mac OS 9 is really outdated in 2020 and will likely be completly dead when Python 3.10 will be released (first Python release when we will be able to remove the module).

About the removal: I would like first write a PEP to propose a process to move old or unmaintained modules from the stdlib to PyPI. The "removal" would mean "move to PyPI" (but yeah, technically it would still be removed from the stdlib).

But I don't want to open a discuss on this hypothetical PEP *here* (I didn't write it yet :-D).