I have two suppositions, meanwhile:
  *  The artifacts are interchanged in no particular orther, and if a DELTA manifest is transferred  before the BASELINE manifest it refers to, it ends up in the 'orphan' table.
  *  The orphan database is written with the rid/baseline members swapped.
<verbatim>
      rid = content_new(p->zBaseline);
      db_multi_exec(
         "INSERT OR IGNORE INTO orphan(rid, baseline) VALUES(%d,%d)",
         rid, p->rid
      );
</verbatim>