Not all proposed features get accepted, specially in how conservative WG 14 tends to be.

Absolutely a true statement, but it should also be noted that WG 14 tends to be more accepting of proposals that have working extension(s) in a major compiler.

Well, that wasn't enough to rescue Annex K, nor to have a way to solve the impending adoption issues.

Which vendor fully implemented Annex K? For several years after C11 was published no vendor fully implemented Annex K, not even the sponsor, Microsoft. I haven't checked in awhile so maybe things have changed.

Well just like here, what clang is implementing with _ExtInt doesn't mean it is what N2472 will look like in the end.

Just like Annex K turned out to look a bit different than what Microsoft sponsored.

Which are still available to Windows developers.

https://docs.microsoft.com/en-us/cpp/c-runtime-library/secur...