There's still quite a few places in the back-end where C-style strings, and null-terminated arrays of such, are used, probably having been carried over from 0.2 code; e.g. I'm thinking MR::Argument::type_choice(). Nowadays these irk me whenever I come across them, and would rather remove the whole lot in favour of std::string / MR::vector / std::initialiser_list etc..