I am getting close to completing PEP 495 implementation, but I need someone to help me with a port to Windows. One of the major obstacles is that my implementation relies heavily on the POSIX localtime_r function which apparently is not available on Windows.
I would also appreciate help from a unittest expert to improve test_datetime. One of the pressing tasks is to make ZoneInfoCompleteTest optional because it takes several minutes to complete.
I am maintaining the patch as a pull request  against the python/cpython repository on github. Code reviews are most welcome.