During the deploy today,
https://www.mediawiki.org/wiki/Parsoid/Deployments#Wednesday.2C_October_26.2C_2016_around_1:15_PT:_ede4353_to_be_deployed_Reverted_to_63f1e151.2C_contentmodel_errs
Parsoid starting spewing these errors. Should the unknown model have fallen back to wikitext?
Separately, we should be running rt on some wikidatawiki pages.