$ git clone -n https://src.fedoraproject.org/rpms/rust-fallible-iterator.git /var/lib/mock/f40-build-2036285-48016/root/chroot_tmpdir/scmroot/rust-fallible-iterator
Cloning into '/var/lib/mock/f40-build-2036285-48016/root/chroot_tmpdir/scmroot/rust-fallible-iterator'...
$ git fetch origin 78c686222fd3c60c7ee6270ae149b7abd2f79b1d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-fallible-iterator
 * [new ref]         78c686222fd3c60c7ee6270ae149b7abd2f79b1d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 78c6862 Update to version 0.3.0