What "publicity issue"?
Sorry for being ambiguous here. I meant the idea that Compat types shouldn't appear in public interfaces. In general, a user is going to want to use Compat because they still want to or must support C++11 while still using modern C++ types and practices. It helps users the most to permit and encourage Compat types in interfaces with the understanding that they become typedefs when the appropriate library support is there. To this end, a user can write a C++11 library using `boost::compat::span` and then seamlessly transition to using it with `std::span` in C++20 mode. In my experience, this is what most people expect and want from a compat library like what's being proposed. And because pre-C++20 has so much developer market share, I think there's tremendous value in a library like Compat. - Christian