$ git clone -n https://src.fedoraproject.org/rpms/gap-pkg-atlasrep.git /var/lib/mock/f38-build-side-42-init-devel-970923-28812/root/chroot_tmpdir/scmroot/gap-pkg-atlasrep
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-970923-28812/root/chroot_tmpdir/scmroot/gap-pkg-atlasrep'...
$ git fetch origin fe0dfc130ec0905a271bdf40a39e4a44128809f0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gap-pkg-atlasrep
 * [new ref]         fe0dfc130ec0905a271bdf40a39e4a44128809f0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fe0dfc1 Use the %gap_arches macro.