Annex C (informative) Compatibility [diff]

C.1 C++ and ISO C++ 2020 [diff.cpp20]

C.1.6 [library]: library introduction [diff.cpp20.library]

Affected subclause: [headers]
Change: New headers.

Rationale: New functionality.

Effect on original feature: The following C++ headers are new: <expected>, <stdatomic.h>, <spanstream>, and <stacktrace>.
Valid C++ 2020 code that #includes headers with these names may be invalid in this revision of C++.