First-order effects

• Developers authenticating Git over SSH can immediately bind their commits and pushes to a physical security key instead of a password, closing the account-compromise vector the announcement targets.
• Every developer still pushing to GitHub with a password now has a visible deadline to migrate, since password support for Git operations is being removed within the year.

Second-order effects

• The SSH change softens the path to GitHub's planned two-factor mandate for code contributors — announced when roughly 16.5% of active users had 2FA enabled — by making strong auth work inside workflows developers already use rather than forcing them onto HTTPS tokens.
• Security key vendors gain a new demand channel: an entire population of command-line-first developers now needs a hardware factor where previously only browser-login users did.

Third-order effects

• If the pattern holds, credential form follows threat model rather than protocol convenience — the arc runs from U2F on web logins, through SSH keys here, to the passkeys public beta that eventually replaces both password and 2FA, leaving passwords absent from the whole Git pipeline.
• Combined with GitHub's shift of secret-leak prevention from opt-in to default push protection across public repositories, the platform is absorbing security decisions developers used to make individually — raising the baseline but concentrating single points of policy failure at GitHub itself.