DRT doesn't dump framesets properly, e.g. in these tests:
  fast/frames/frame-src-attribute.html
  fast/parser/iframe-sets-parent-to-javascript-url-expected.txt
  fast/parser/iframe-sets-parent-to-javascript-url-expected.txt
  fast/parser/xml-colon-entity-expected.txt

Typical result is
@@ -3,8 +3,7 @@
 ALERT: 3
 ALERT: 4

-
 --------
-Frame: '<!--framePath //<!--frame0-->-->'
+null
 --------
 PASS