$ git clone -n https://src.fedoraproject.org/rpms/rust-git-version.git /var/lib/mock/f45-build-41899-786/root/chroot_tmpdir/scmroot/rust-git-version
Cloning into '/var/lib/mock/f45-build-41899-786/root/chroot_tmpdir/scmroot/rust-git-version'...
$ git fetch origin 04f29055f8ce3dd4e93dbdc1b252bc8783115ee1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-git-version
 * [new ref]         04f29055f8ce3dd4e93dbdc1b252bc8783115ee1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 04f2905 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild