$ git clone -n https://src.fedoraproject.org/rpms/rust-rustc-stable-hash.git /var/lib/mock/f45-build-44567-815/root/chroot_tmpdir/scmroot/rust-rustc-stable-hash
Cloning into '/var/lib/mock/f45-build-44567-815/root/chroot_tmpdir/scmroot/rust-rustc-stable-hash'...
$ git fetch origin 3720494b9e06b91233cd019b4be12b61c4ba3694:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-rustc-stable-hash
 * [new ref]         3720494b9e06b91233cd019b4be12b61c4ba3694 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3720494 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild