$ git clone -n https://src.fedoraproject.org/rpms/picard.git /var/lib/mock/f41-build-side-1-2753450-31224/root/chroot_tmpdir/scmroot/picard
Cloning into '/var/lib/mock/f41-build-side-1-2753450-31224/root/chroot_tmpdir/scmroot/picard'...
$ git fetch origin d3a58af5f0096620206ca09edfca0cb59c789933:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/picard
 * [new ref]         d3a58af5f0096620206ca09edfca0cb59c789933 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d3a58af rhbz#2304294