GitHub now supports SSH commit verification, so you can sign commits and tags locally using a self-generated SSH public key, which will give others confidence about the origin of a change you have made. If a commit or tag has an SSH signature that is cryptographically verifiable, GitHub makes the commit or tag "Verified" or "Partially Verified."
If you already use an SSH key to authenticate with GitHub, you can now upload the same or a different key pair’s public key to use it as a signing key. There is no limit to the number of signing keys you can add to your account. For more information, visit SSH Commit Verification in the GitHub documentation.
Today we are deprecating the theme picker we introduced in 2012 for GitHub Pages.
While this experience allowed users to preview a theme in the user interface, we are doing this to increase the security of github.com.
You can of course continue to use any Jekyll theme you want with Pages, and publish beautiful sites with a small configuration change.