Why would we never know? Quoting from the blog post: "The specific reasons given were that [...]" followed by a bullet list. Your guess is unwarranted speculation.
sums = [s for s in [0] for x in data for s in [s + x]]
Why would you do "for s in" twice? Is that intentional? It would make more sense to me if the variables would have been different. And why would you want to add 0 to numbers?! Curious about a real world use case for this.