In C++23, there is a typo in "Cross-references from ISO/IEC 14882:2020". It states re.def see intro.refs. However, if I interpret correctly, that is not correct, the r in refs should be replaced by a d, since the definitions of the regular expressions library from the C++20 Standard (i.e., [re.def]) appear in C++23 among other definitions in [intro.defs].

On the other hand, this cross-reference should not appear anymore in the next published version of the C++ Standard. I just mention it since I would say it is still present here: