It is, it was then used regularly across project as a sign that touching this code is very dangerous and should not be done except by the experts of that codeba

It is, it was then used regularly across project as a sign that touching this code is very dangerous and should not be done except by the experts of that codebase. Fun nostalgia to see it out there :) Note that I doubt anybody ever got fired for modifying these parts of the code. In particular, automatic refactors would have modified these (safely); and it’s a scary warning about negative consequences of messing up.