$ git clone -n https://src.fedoraproject.org/rpms/rust-uu_cut.git /var/lib/mock/f40-build-774038-127569/root/chroot_tmpdir/scmroot/rust-uu_cut
Cloning into '/var/lib/mock/f40-build-774038-127569/root/chroot_tmpdir/scmroot/rust-uu_cut'...
$ git fetch origin 4a8400a639db1e8ac55c9a5fc6f73bf48e3a594b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-uu_cut
 * [new ref]         4a8400a639db1e8ac55c9a5fc6f73bf48e3a594b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4a8400a Initial package (rhbz#2257473)