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 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 mean time we have updated the instructions for consuming components from the 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!