This tool will migrate the external_foaf_url user property from the global database down to user clusters. This may or may not affect you very much, but since it is a new tool, I want everybody to be aware that it's there.
Currently it deletes the data from the global after it's done, since half the point is to free up space on the global. If you don't want it deleting data automatically, you should comment out that line in bin/upgrading/migrate-userprop.pl. (Search for DELETE.)