Web service works: http://dbpedia.informatik.uni-leipzig.de:9998/server/extraction/en/extract?title=Warsaw&revid=&format=json&extractors=custom
but for https://meta.wikimedia.org/wiki/Grants:Project/DBpedia/GlobalFactSyncRE we would need additional information already implemented in the tempate-test branch.
@jfrey can you list all extractors for custom or post or link the property file