I'd like to request a formal Boost review for the Variant2 library, https://github.com/pdimov/variant2. Variant2 contains an implementation of a variant<T...> type that is an almost conforming std::variant, except it doesn't require C++17 and supports C++11 and above. It's also never valueless and has a few other extensions. The same library also contains an expected<T, E...> type, which is like the proposed std::expected<T, E>, but supports more than one error type. expected<> is not yet production-ready and has no test suite, but I will finish it if the library is accepted. The documentation for the variant<T...> class is at https://pdimov.github.io/variant2/index.html. If anyone would like to step forward to manage the review, please do.