$ git clone -n https://src.fedoraproject.org/rpms/rust-stability.git /var/lib/mock/f45-build-45138-821/root/chroot_tmpdir/scmroot/rust-stability
Cloning into '/var/lib/mock/f45-build-45138-821/root/chroot_tmpdir/scmroot/rust-stability'...
$ git fetch origin 843d53fdf44339cd8c4bdbc8b6c5c7aa777f01ec:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-stability
 * [new ref]         843d53fdf44339cd8c4bdbc8b6c5c7aa777f01ec -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 843d53f Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild