const out=[];
for (const f of document.querySelectorAll('iframe')) {
  let accessible=false, keys=null, err=null;
  try { const w = f.contentWindow; accessible = !!w.document; 
        keys = Object.keys(w).filter(k=>/bridge|rpc|pcb|editor|route|Route/i.test(k)).slice(0,25);
  } catch(e){ err=String(e).slice(0,80); }
  out.push({src:String(f.src).slice(0,120), id:f.id, cls:String(f.className).slice(0,40), accessible, keys, err});
}
return out;