$ git clone -n https://src.fedoraproject.org/rpms/rust-instability.git /var/lib/mock/f45-build-42584-795/root/chroot_tmpdir/scmroot/rust-instability
Cloning into '/var/lib/mock/f45-build-42584-795/root/chroot_tmpdir/scmroot/rust-instability'...
$ git fetch origin 665b0d936bd7b331ad5a56189fb3aee5b2e6d930:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-instability
 * [new ref]         665b0d936bd7b331ad5a56189fb3aee5b2e6d930 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 665b0d9 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild