@pquentin, @illia-v and I discussed the current state of the pyOpenSSL module:

• There hasn't been any community effort that we know of to pull the pyOpenSSL module out of urllib3 and support it elsewhere.
• There hasn't been any addition to Python to support in-memory certificates
• Support for in-memory certificates is a major barrier to adoption of urllib3 v2.0
• pyOpenSSL support isn't a /ton/ of support burden, it isn't zero though. We will likely want to remove it if any of the above change.

For these reasons, we've decided to un-deprecate pyOpenSSL and not remove the urllib3.contrib.pyopenssl module in v2.1.0.