$ git clone -n https://src.fedoraproject.org/rpms/highfive.git /var/lib/mock/f39-build-1785818-41710/root/chroot_tmpdir/scmroot/highfive
Cloning into '/var/lib/mock/f39-build-1785818-41710/root/chroot_tmpdir/scmroot/highfive'...
$ git fetch origin 6e4ae0315ed68a55375c810a91d5e42f2d206a92:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/highfive
 * [new ref]         6e4ae0315ed68a55375c810a91d5e42f2d206a92 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6e4ae03 Stop building for i686