See https://abseil.io/tips/ for some idea of the kinds of guidance these kinds of teams work to provide, at least at Google. I worked on the “C++ library team” at Google for a number of years.

These roles don’t really have standard titles in the industry, as far as I’m aware. At Google we were part of the larger language/library/toolchain infrastructure org.

Much of what we did was quasi-political … basically coaxing and convincing people to adopt best practices, after first deciding what those practices are. Half of the tips above were probably written by interested people from the engineering org at large and we provided the platform and helped them get it published.

Speaking to the original question, no, there were no teams just manually reading code and looking for mistakes. If buggy code could be detected in an automated way, then we’d do that and attempt to fix it everywhere. Otherwise we’d attempt to educate and get everyone to level up their code review skills.