New attribute typemustmatch

[Shelley Powers]

A new attribute was added to the object element.

Tracker change
http://html5.org/tools/web-apps-tracker?from=6221&to=6222

The change in the HTML5 specification

http://dev.w3.org/html5/spec/the-iframe-element.html#attr-object-typemustmatch

I could find no bug at the W3C to account for this change, nor any 
discussion within the HTML WG email lists to account for this change.

What is the justification for this significant change? Was this change 
made within LC procedures?

Shelley