$ git clone -n https://src.fedoraproject.org/rpms/gap-pkg-polymaking.git /var/lib/mock/f38-build-side-42-init-devel-962826-28791/root/chroot_tmpdir/scmroot/gap-pkg-polymaking
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-962826-28791/root/chroot_tmpdir/scmroot/gap-pkg-polymaking'...
$ git fetch origin 933d989ff6f9fde5997f635a1ad9e3e50a4d8d1e:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gap-pkg-polymaking
 * [new ref]         933d989ff6f9fde5997f635a1ad9e3e50a4d8d1e -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 933d989 Use the %gap_arches macro.