$ git clone -n https://src.fedoraproject.org/rpms/R-GenomicAlignments.git /var/lib/mock/f38-build-724156-99404/root/chroot_tmpdir/scmroot/R-GenomicAlignments
Cloning into '/var/lib/mock/f38-build-724156-99404/root/chroot_tmpdir/scmroot/R-GenomicAlignments'...
$ git fetch origin 38e9efbb771f1c6bdbc40b6a8c4571c9410e684d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-GenomicAlignments
 * [new ref]         38e9efbb771f1c6bdbc40b6a8c4571c9410e684d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 38e9efb R-maint-sig mass rebuild