Minor nitpick: I'd prefer to see size denoted as 12kB (or 12 KB) rather than 12kb, where I have to wonder whether it means kilobit or kilobyte. Note that Justine has also worked on languages whose programs consists of bits [1].
It's 12 kB, aka 96 kb.
The HN submission's title is not even the article's title, which is "How Fat Does a Fat Binary Need To Be?"
wat
HN auto-title cases submissions titles and removes any numbers prefixing the title string. So “7 KB” would be changed to “Kb”.