$ git clone -n https://src.fedoraproject.org/rpms/R-farver.git /var/lib/mock/f38-build-724261-99404/root/chroot_tmpdir/scmroot/R-farver
Cloning into '/var/lib/mock/f38-build-724261-99404/root/chroot_tmpdir/scmroot/R-farver'...
$ git fetch origin 4c484bb248d8221acc76ac51428fe1da9a49df74:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-farver
 * [new ref]         4c484bb248d8221acc76ac51428fe1da9a49df74 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4c484bb R-maint-sig mass rebuild