You know, I'm not sure what I was thinking when I wrote that. There's no real great reason to avoid doing it other than download size, and I doubt that's a huge issue. Right now I think they're just doing releases as a .tar.gz archive of the checkout files. That'd mean an extra "build" step at release time, but that's probably trivial to automate.

That said, the source text files for the documentation are included, and whatever markup format they use (reStructuredText?) is relatively legible. HTML docs would be better, though.