Basically old https://secure.phabricator.com/T6491 but creating this ticket as several other tickets in Wikimedia Phabricator would depend on this.
https://secure.phabricator.com/D11419#107322 is relevant here.
Most relevant existing upstream code: https://we.phorge.it/rP19be32656f84b43ede8e6a5bb84a2e3c8ac7ac40. See https://we.phorge.it/book/contrib/article/event_triggers/ once that is not a 404 anymore, patch was https://we.phorge.it/D26204)
See Also: