This is just a note that with Benjamin's help we've moved the ambv/typehinting repo on GitHub into the python org, so its URL is now https://github.com/python/typing .
This repo was used most intensely for discussions during PEP 484's drafting period. It also contains the code for typing.py, repackaged for earlier releases on PyPI. The issue tracker is still open for proposals to change PEP 484, which is not unheard of given its provisional status. If you find a pointer to the original location of this repo in a file you can update, please go ahead (though GitHub is pretty good at forwarding URLs from renamed repos).