$ git clone -n https://src.fedoraproject.org/rpms/rust-cexpr.git /var/lib/mock/f45-build-40728-775/root/chroot_tmpdir/scmroot/rust-cexpr
Cloning into '/var/lib/mock/f45-build-40728-775/root/chroot_tmpdir/scmroot/rust-cexpr'...
$ git fetch origin 88c4b0b56b75cfb99a455f803ec30dbc3401d8b7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-cexpr
 * [new ref]         88c4b0b56b75cfb99a455f803ec30dbc3401d8b7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 88c4b0b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild