static void ai_spec_relRewrite(Web web) {
  for (WebRelation r : web_relationObjects(web)) {
    S rel = web_text(r);
    for (S newRel : ai_texts_verified(rel, "[relation] rewrites to", "$X"))
      postDerivedFromWeb(web, web_text(r.a), newRel, web_text(r.b));
  }
}