The change emphasize the leading zero for one-digit day numbers. date_to_string sounds so human readable, but the output is not what I expect.
BTW: Why did you choose the always two-digit variant '%d' over the natural '%e' one?
Change day example to a one-digit
Not sure why we chose it. The last commit I can get to easily is cc73f04 by @mojombo when he moved the site to the site/ dir so I'm not sure what happened before then.
Update history to reflect merge of #1663