$ git clone -n https://src.fedoraproject.org/rpms/gap-pkg-mapclass.git /var/lib/mock/f38-build-side-42-init-devel-907756-28633/root/chroot_tmpdir/scmroot/gap-pkg-mapclass
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-907756-28633/root/chroot_tmpdir/scmroot/gap-pkg-mapclass'...
$ git fetch origin 65891116f4d0d4c50e916bdb8ffbd4a168cfe666:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gap-pkg-mapclass
 * [new ref]         65891116f4d0d4c50e916bdb8ffbd4a168cfe666 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6589111 Use the %gap_arches macro.