$ git clone -n https://src.fedoraproject.org/rpms/rust-lab.git /var/lib/mock/f45-build-42816-796/root/chroot_tmpdir/scmroot/rust-lab
Cloning into '/var/lib/mock/f45-build-42816-796/root/chroot_tmpdir/scmroot/rust-lab'...
$ git fetch origin cc715e64d34f0e8f1ffedb15d371f5e3e56e7aae:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-lab
 * [new ref]         cc715e64d34f0e8f1ffedb15d371f5e3e56e7aae -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cc715e6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild