Same here. 20+ years professional experience with a bunch of different companies, industries, languages, and locales. TODO/FIXME are the only ones I'd consider

Same here. 20+ years professional experience with a bunch of different companies, industries, languages, and locales. TODO/FIXME are the only ones I'd consider universal, and I have literally never seen anyone use XXX. I don't doubt that people use it or even that it's common, I'm just confused as to how I could've missed it. Maybe it's not as common as everyone here thinks? Or maybe it's common in corners of the industry that I haven't spent much time in (like web development). No idea.