woah, TIL that all pages on HN are a <table>!
After having a PNG decoder, and a BMP and ICO decoder to support favicons in tabs, only then did I find out that this resource is an SVG :-) An SVG renderer is quite a piece of work...
Yet another interesting detail: the Javascript is quite simpler, it seems to be mostly about submitting votes and collapsing comments. A small Javascript interpreter and just a few DOM hooks would be enough to support comment collapse toggling. Maybe that will come later :-)