$ git clone -n https://src.fedoraproject.org/rpms/rust-str_indices.git /var/lib/mock/f40-build-2658240-66917/root/chroot_tmpdir/scmroot/rust-str_indices
Cloning into '/var/lib/mock/f40-build-2658240-66917/root/chroot_tmpdir/scmroot/rust-str_indices'...
$ git fetch origin 71c9a2b6dd905262f2d24809a6c5e691c61d6380:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-str_indices
 * [new ref]         71c9a2b6dd905262f2d24809a6c5e691c61d6380 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 71c9a2b Update to version 0.4.3 (rhbz#2248581)