Which Evan Balster provided a while back. I much prefer it over <$reveal> (perhaps only for semantic reasons). And the fact he allowed <$else> to be used following a falsey <$reveal> is pretty cool, too, See: Condition Plugin
I have a nagging feeling I read somewhere that @joshuafontany took over the condition plugin along with the formula plugin GitHub - EvanBalster/TiddlyWikiFormula: Functional Formulas for TiddlyWiki, in the style of Excel and Google Sheets · GitHub