$ git clone -n https://src.fedoraproject.org/rpms/jl.git /var/lib/mock/f41-build-side-1-2800188-32800/root/chroot_tmpdir/scmroot/jl
Cloning into '/var/lib/mock/f41-build-side-1-2800188-32800/root/chroot_tmpdir/scmroot/jl'...
$ git fetch origin 20afd195356c5be626bc242c695ebe9f4cfd21ca:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/jl
 * [new ref]         20afd195356c5be626bc242c695ebe9f4cfd21ca -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 20afd19 Control.Monad provides foldM