Basically, the wording is so that they can advise implementations to complain on potentially invalid-in-the-future uses of "potentially reserved identifiers", b

Basically, the wording is so that they can advise implementations to complain on potentially invalid-in-the-future uses of "potentially reserved identifiers", but invalid uses of actually reserved identifiers are still "requires no diagnostics". They feel that allows them to extend the already way too vast amount of reserved identifiers even further without any reservations. Yes, that means that an implementation will warn you that your code might break in the future, but on the day when it actually breaks, it will just stop complaining. Why they could not just mandate detecting invalid uses of reserved identifiers is beyond me.