$ git clone -n https://src.fedoraproject.org/rpms/rust-below.git /var/lib/mock/f42-build-3285363-41413/root/chroot_tmpdir/scmroot/rust-below
Cloning into '/var/lib/mock/f42-build-3285363-41413/root/chroot_tmpdir/scmroot/rust-below'...
$ git fetch origin f22f672eb49335ffb5f25ae145d225706dd168d5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-below
 * [new ref]         f22f672eb49335ffb5f25ae145d225706dd168d5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f22f672 Update to 0.9.0; Fixes: RHBZ#2347633