$ git clone -n https://src.fedoraproject.org/rpms/systemd.git /var/lib/mock/f41-build-809914-146381/root/chroot_tmpdir/scmroot/systemd
Cloning into '/var/lib/mock/f41-build-809914-146381/root/chroot_tmpdir/scmroot/systemd'...
$ git fetch origin 74810c5bc4fe7d872e54c253447ffd61bbc8839f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/systemd
 * [new ref]         74810c5bc4fe7d872e54c253447ffd61bbc8839f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 74810c5 Fix release field