It is live. Within an extremely short turnaround time, the Sonatype Operations team has coordinated certificates and other setup with our excellent CDN provider Fastly, and you can now all enjoy the content of the Maven Central repository via HTTPS/SSL.
Going forward, we urge all upstream projects to adopt the secure URL as part of their default configuration. In the meantime, we have updated the instructions for consuming components from the Maven Central repository, with all the details necessary for your repository manager, build tool or other access mode you are using.
We hope you enjoy this new feature and look forward to your feedback.