Repository owners that are not interested in batch change changesets can opt out so that their repository will be skipped when a batch spec is executed.
To opt out: create a file called .batchignore at the root of the repository you wish to be skipped. src batch [apply|preview] will now skip that repository if it's yielded by the on part of the batch spec.
NOTE: You can use the
-force-override-ignoreflag to override that behaviour and not skip any ignored repositories.