Hi Arnaud, such a change is out of scope for PEP 466. To minimise the scale of the changes in a maintenance release, it was deliberately limited to provide the core infrastructure, so at least third party libraries like requests can support SNI in Python 2, without touching every networking module in the Python 2 standard library.

However, you're welcome to write a follow up PEP suggesting expanding the scope of the changes out to at least offering SNI support in other standard library modules. While I can't promise such a proposal would be approved, I do agree the question is worth asking. The risk of that change can then be independently assessed vs advising users that need SNI support in Python 2 to install a third party module like requests. (The bootstrapping problem is likely to be addressed by backporting the relevant parts of PEP 453, although that project too is in need of a volunteer to write the enhancement proposal).