Adding any globals should be a carefully-considered change. User-defined functions are global by default, and although there are (now) much better ways to write PHP libraries, I can absolutely see some old library defining array_find (one of the new global functions in 8.4) in an incompatible way and breaking new code that attempts to use the built-in function.

Sure, you can’t touch the existing pile of globals, but at least stop pouring fuel on that particular fire…