$ git clone -n https://src.fedoraproject.org/rpms/gkrellm.git /var/lib/mock/f42-build-side-1-3498236-45962/root/chroot_tmpdir/scmroot/gkrellm
Cloning into '/var/lib/mock/f42-build-side-1-3498236-45962/root/chroot_tmpdir/scmroot/gkrellm'...
$ git fetch origin 2b578a6ef9aba7d44b88846f7fb0c6aed3f42fc5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gkrellm
 * [new ref]         2b578a6ef9aba7d44b88846f7fb0c6aed3f42fc5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2b578a6 Fix systemd unit file to point to correct gkrellmd location