$ git clone -n https://src.fedoraproject.org/rpms/rust-ron.git /var/lib/mock/f42-build-side-1-3499070-45964/root/chroot_tmpdir/scmroot/rust-ron
Cloning into '/var/lib/mock/f42-build-side-1-3499070-45964/root/chroot_tmpdir/scmroot/rust-ron'...
$ git fetch origin 42c45e832ab6b0d0027984f17da54abb520350fe:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-ron
 * [new ref]         42c45e832ab6b0d0027984f17da54abb520350fe -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 42c45e8 Update to version 0.9.0; Fixes RHBZ#2353220