https://www.mediawiki.org/w/index.php?title=Topic:T6wraj6le0b4394w&action=history shows unstyled mw-plusminus text. This used to be green and red.
Most likely caused by 9e458504c7b49097ac10c9fc185ee2b2447b8e23. Basically just needs the mediawiki.special.changeslist module, though ideally this wouldn't need to be hardcoded in Flow.