C ++ 17 std :: optional in g ++?

cppreference.com - std :: optional identifies std :: optional as available "since C ++ 17". C ++ Standards Support in GCC Language Features - C ++ 1z C ++ 17 Lists I don't see std :: optional in the list. Has std :: optional been documented for g ++?

#include <string>
#include <iostream>
#include <optional>

// optional can be used as the return type of a factory that may fail
std::optional<std::string> create(bool b) {
    if(b)
        return "Godzilla";
    else
        return {};
}

int main()
{
    std::cout << "create(false) returned "
              << create(false).value_or("empty") << '\n';

    // optional-returning factory functions are usable as conditions of while and if
    if(auto str = create(true)) {
        std::cout << "create(true) returned " << *str << '\n';
    }
}