In the US, the punctuation is supposed to be inside of the quotes, even if that punctuation wasn't actually part of what's being quoted. So if somebody says "your mother sews socks that smell," the quoted partial bit would be typed as "your mother sews socks." In Britain it would be "your mother sews socks". The difference might not be really obvious visually; it's whether that period (which is required to end the sentence) is before the end quote or after it. Apparently programmers in the US (like I used to be) have gravitated towards the British style because with string variables (which are generally delimited by quotes) you can't be farting around with adding phantom punctuation inside the quotes, even if it is grammatically correct here.