tedster - 10:03 pm on Dec 1, 2010 (gmt 0)
There is an inline frame later in the document, but I take it that the frameset spec is not necessary for that?
That is correct. The frameset DTD only applies to the actual <frame> attribute.
In fact, in HTML 5, the <iframe> element will still be supported, but not the <frame> element. Reference [w3schools.com]