$ git clone -n https://src.fedoraproject.org/rpms/fedora-jam-backgrounds.git /var/lib/mock/f41-build-side-1-3049579-37900/root/chroot_tmpdir/scmroot/fedora-jam-backgrounds
Cloning into '/var/lib/mock/f41-build-side-1-3049579-37900/root/chroot_tmpdir/scmroot/fedora-jam-backgrounds'...
$ git fetch origin 037279619741e18fe40158cba02f9801e648b1b3:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fedora-jam-backgrounds
 * [new ref]         037279619741e18fe40158cba02f9801e648b1b3 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0372796 convert license to SPDX