$ git clone -n https://src.fedoraproject.org/rpms/fast_float.git /var/lib/mock/f40-build-1817473-24911/root/chroot_tmpdir/scmroot/fast_float
Cloning into '/var/lib/mock/f40-build-1817473-24911/root/chroot_tmpdir/scmroot/fast_float'...
$ git fetch origin fddd5f00878438998d4bf4c547219c3c2ce364bd:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fast_float
 * [new ref]         fddd5f00878438998d4bf4c547219c3c2ce364bd -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at fddd5f0 Update to 6.1.3 (close RHBZ#2299620)