$ git clone -n https://src.fedoraproject.org/rpms/rust-coreos-installer.git /var/lib/mock/f42-build-3490655-45852/root/chroot_tmpdir/scmroot/rust-coreos-installer
Cloning into '/var/lib/mock/f42-build-3490655-45852/root/chroot_tmpdir/scmroot/rust-coreos-installer'...
$ git fetch origin b3ef4010940b3a5e8c8801531398a508d80f45fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-coreos-installer
 * [new ref]         b3ef4010940b3a5e8c8801531398a508d80f45fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b3ef401 Bump release version to 0.23.0-6