There are several words in Korean that could be translated as everywhere. Manbang is one of them.

According to Naver's Korean-Korean dictionary there are four different words spelled "manbang" (three with Chinese roots, one a colloquialism):

1. Every place
2. A synonym for manguk (all the nations of the world)
3. In baduk (the game Go), what is said when you tally up the points and the difference is at least 91
4. A colloquial abbreviation short for "manhwa bang" (comic book store)

Abbreviations where one combines the first syllable of each word are common in South Korea, though I'm not sure about North Korea. If they do, then I suspect the fourth definition may have been the intended meaning. It's also worth noting that TFA never claims manbang translates as everywhere; that was added by the submitter.

Both British English and American English use the expression "I couldn't care less" to mean the speaker does not care at all. In American English, the phrase "I could care less" (without the "n't") is synonymous with this in casual usage. Intonation no longer reflects the originally sarcastic nature of this variant, which is not idiomatic in British English and might be interpreted as anything from nonsense to an indication that the speaker does care.