$ git clone -n https://src.fedoraproject.org/rpms/copr-keygen.git /var/lib/mock/f42-build-side-1-3502123-45977/root/chroot_tmpdir/scmroot/copr-keygen
Cloning into '/var/lib/mock/f42-build-side-1-3502123-45977/root/chroot_tmpdir/scmroot/copr-keygen'...
$ git fetch origin 72b764869b1edfcfe9ffa11cf3fa91245c1b5805:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/copr-keygen
 * [new ref]         72b764869b1edfcfe9ffa11cf3fa91245c1b5805 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 72b7648 Update copr-keygen to 2.1-1