$ git clone -n https://src.fedoraproject.org/rpms/fast_float.git /var/lib/mock/f41-build-side-1-2811286-32927/root/chroot_tmpdir/scmroot/fast_float
Cloning into '/var/lib/mock/f41-build-side-1-2811286-32927/root/chroot_tmpdir/scmroot/fast_float'...
$ git fetch origin a0031e191adad6f9c4717cde3ae0e8cc2fcd9d39:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/fast_float
 * [new ref]         a0031e191adad6f9c4717cde3ae0e8cc2fcd9d39 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a0031e1 Update to 6.1.6 (close RHBZ#2310850)