$ git clone -n https://src.fedoraproject.org/rpms/plasma-workspace-wallpapers.git /var/lib/mock/f40-build-2141638-50851/root/chroot_tmpdir/scmroot/plasma-workspace-wallpapers
Cloning into '/var/lib/mock/f40-build-2141638-50851/root/chroot_tmpdir/scmroot/plasma-workspace-wallpapers'...
$ git fetch origin 19ce755c8b74489f6a878b9642935ada515d89fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-workspace-wallpapers
 * [new ref]         19ce755c8b74489f6a878b9642935ada515d89fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 19ce755 5.91.0