static L<Web> ai_getWebs(S id) {
  if (!possibleGlobalID(id)) null;
  ret ai_getWebs(asGlobalID(id));
}

static L<Web> ai_getWebs(GlobalID id) {
  if (id == null) ret emptyList();
  Web primary = ai_getWeb(id); // also queries virtual indices
  if (primary == null) ret emptyList();
  L<Web> l = ll(primary);
  
  // add duplicate webs (shouldn't have any anyway)
  l.addAll(dropFirst(allWebsByID().get(id)));
  ret l;
}