If a user could upload their public GPG key to their account (as they can their public SSH key), GitHub could easily verify signed commits, which git itself all

If a user could upload their public GPG key to their account (as they can their public SSH key), GitHub could easily verify signed commits, which git itself allows with `git commit --gpg-sign[=<keyid>] ...`. It would be trivial for them to shell out to `git verify-commit <commit>` in order to verify that the claimed originator has signed his commits with a key tracked by github (by email address, which can belong to only one github user).