A few, not completely unrelated, items:
In the process Jacques Distler discovered that the W3C page which recommends a regular expression for checking for proper XML/UTF-8 allows through UTF-8 encodings of U+FFFE and U+FFFF.
Meanwhile, I was using XML Builder to produce HTML and discovered that XML builder doesn’t ensure that tags are properly closed: testcase/monkeypatch. My experience with the XML Builder maintainer is much better than my experience with the REXML maintainer, so I expect that this issue will be promptly addressed.
Speaking of promptness, if anybody could track down Jeremy Zawodny, I’d appreciate it. Actually, it would be much better if those that back MediaRSS and those that support iTunes could simply review HTML5’s video tag and figure out what needs to be added and how to use it in the context of a feed, life would be so much better.