PostgreSQL has been around for almost 27 years (and even longer, if you include the Ingress and Post-Ingress eras). And things, well things, they tend to accumulate, to quote Trent Reznor, heh.
On a related note, one could say that the C++ Core Guidelines[1] at least partially represent such a list. 55 matches for “don't use” and 247 for “avoid”, although not all of them are about language features, obviously.
I think that every platform that's old and has backwards compatibility has to have such a page - because there inevitably will be features for which we (now!) know that there are better ways to achieve the same goal, but they have to stay there for compatibility reasons.
