[Jongseong]

Thanks, I should have made the connection to encoding immediately. I've found more info in <a href="http://www.theguardian.com/technology/2014/dec/02/north-kore... following Guardian article</a>:

“In the file we had a line with broken characters. Those characters didn’t render right under any encoding, except EUC-CN [Chinese] and EUC-KR [Korean] … In this case, the readme.txt file could be read fine under either EUC-CN and EUC-KR, which means the file was most likely generated from a computer set in either Chinese or Korean – or the hacker deliberately converted the file (which seems unlikely),” Karpeles said.

I should add that EUC-KR is a South Korean legacy character encoding, but the corresponding North Korean encoding (EUC-KP?) is hardly ever supported so in practice North Koreans would be likely to use EUC-KR.