I just noticed that Raft is using std::experimental::aligned_accessor in its Kokkos fork in its thirdparty/ subdir [[link](https://github.com/rapidsai/raft/blob/8bd5605f53500b7e3f70579c521fdbfcec6439e5/cpp/include/raft/thirdparty/mdspan/include/experimental/__p0009_bits/aligned_accessor.hpp)]. It builds fine on C++20. It would be very nice to upstream it to kokkos/mdspan mainline.
