Suggested during security review:
- Make limit of importable number revisions (file/file page) into a $wg. Likely useful for WMF wikis when we're not collecting across the interwebs, so we more isn't necessarily gonna be much slower
- If a page hits the limit, maybe import (or offer to) the newest $number rather than just stopping completely? Gonna be useful for WMF when we still want to import. Obviously, we can just Special:Export the file page history and import it...