So, one kind of structure that wraps a leaf is a bud. What I'd like to do by introducing a "bud directory" concept is not to limit our choices, but simply to develop some terminology to help us talk to each other about the choices we're making. The mainstream methods, as far as I can tell, are

  1. fixed name wrapper (eg, "obj")
  2. variable name wrapper formed from entire id
  3. variable name wrapper formed from some interesting part of the id