$ git clone -n https://src.fedoraproject.org/rpms/R-lubridate.git /var/lib/mock/f38-build-724436-99434/root/chroot_tmpdir/scmroot/R-lubridate
Cloning into '/var/lib/mock/f38-build-724436-99434/root/chroot_tmpdir/scmroot/R-lubridate'...
$ git fetch origin 696fc70be66c857ce5f91d2f108d0007a4952997:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-lubridate
 * [new ref]         696fc70be66c857ce5f91d2f108d0007a4952997 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 696fc70 R-maint-sig mass rebuild