[boost] [policy_ptr]std_ptrs.hpp's include target missing & incomplete shared_ptr emulation

The file: std_ptrs.hpp contains: #include "policy/boost.hpp" yet there's no policy/boost.hpp. However, there is: boost_policies.hpp However, in that file, the shared_storage class, contains: detail::shared_count count_; IOW, count_, unlike that in shared_ptr, contains no information about the type of pointee_; hence, I can't understand how policy_ptr's smart_ptr<...>, can emulate boost's shared_ptr with existing policies. What have I missed?