As you may have guessed, I've been working on the release notes for 1.21. Please look over them and improve them if you can.
In the process, I came across the ContentHandler blurb. I don't recall this being discussed on-list, but, from looking at the documentation for it, it looks pretty awesome. I've used some of my editorial powers to say, in the release notes:
Extension developers are expected to create additional types in the future. These might support LaTeX or other forms of markup.
Is this correct? It sounds like a really big thing, if it is.