$ git clone -n https://src.fedoraproject.org/rpms/root.git /var/lib/mock/f38-build-side-42-init-devel-835231-28387/root/chroot_tmpdir/scmroot/root
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-835231-28387/root/chroot_tmpdir/scmroot/root'...
$ git fetch origin 088e995d07cf6c050f713cca636bdd81d00f47fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/root
 * [new ref]         088e995d07cf6c050f713cca636bdd81d00f47fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 088e995 Update to 6.28.02