When I put this in Google Translate, it auto-detects Japanese and gives me "outer cover." When I specify Chinese, it just says "cousin." So it's not trivial to look up.

Presumably you would google "CNBiaoJie" and find Apple documentation explaining the concept.

(As an aside, Google Translate is a terrible way to look up the definitions of specific words. It is not a Chinese-English dictionary and doesn't try to be. Wiktionary would be a much better free option.)

Google translate and Bing translate are extremely unreliable for ideographic languages.

And then every time you re-read the code you have to look it up to understand 1/ what the hell is even this and 2/ is it the right one at the right place.

Yes, which I think is easier than having to parse and understand this identifier every time you see it.

Especially since after a few times you will remember what it means and not have to look it up anymore. There's a good reason we use jargon for complicated concepts rather than re-explaining them every time they're used. "while" is a lot easier to understand once its meaning has been explained to you than "EveryTimeWeGetHereCheckIfThisConditionIsTrueAndExecuteThisCodeBlockAndJumpBackHereIfSo".

Whereas with this English symbol that might not fit on a screen, there are none of those problems?! If the concept is foreign to you to begin with, but you have to care about it for some reason, you're going to have a bad time with either 1 or 2 no matter what the symbol is. (Though I agree that transliterating to BiaoJie would make it easier.)