Stock market indicators in China are reversed in colour from the western world (up=red, down=green). Sometimes I wonder if Github really should be flipping the colours on diffs for Chinese language users for the sake of consistency.

To be fair to the Chinese, whether a price going up or down is alarming or encouraging depends on whether one wishes to buy or to sell.

Do you know if that is because up is generally "bad" for them, or because red means "good" and green means "bad"?

Red is considered good and prosperous. Hence the huge amount of red in Chinese culture.

https://en.m.wikipedia.org/wiki/Color_in_Chinese_culture#Red