While looking into some Phabricator search anomalies, I stumbled upon the phabricator_search.search_documentfield_BKUP table in MariaDB on phab1004.
I could not find any pointers why and when that table got renamed (no pointers in T146673 or T156373 which I guess are most related.
In my understanding, rPHAB719dd6d3f44245e935b21291a59338a819938c49 should have dropped that entire phabricator_search.search_documentfield table anyway.
Which likely did not happen in our installation due to that earlier table rename, I assume?
(Note to my future self: Docs about this on https://we.phorge.it/book/contrib/article/database/ are incorrect per https://we.phorge.it/Q82)