static Set<S> aggressivelyCollectPossibleGlobalIDs(S s) {
  new LinkedHashSet<S> ids;
  if (s == null) ret ids;
  Matcher matcher = matcher("[^a-z]([a-z]{16})(?![a-z])", " " + s);
  while (matcher.find())
    ids.add(matcher.group(1));
  ret ids;
}