As promised, a non-newsy thread on Korean Chinese food:

Chinese food in Korea is generally considered delivery food, though these days the traditional cuisine from the mainland has gotten more popular and there are some very upscale places serving high-end cuisine.

But some of the most popular go-to Chinese foods in Korea are localized versions of Chinese food or sometimes just dishes that have no clear cousins in China. We see this with some American Chinese dishes, too.

짜장면 (jjajangmyeon) is one of the two ubiquitous Korean Chinese dishes. It's a Korean adaptation of the Chinese dish 炸酱面 (zhajiangmian). But unlike the original dish, which is savory, 짜장면 is sweet.

There are also several variations to 짜장면, one of which is a spicy variant called 사천짜장. 사천=hanja pronunciation of Sichuan (四川), a province known for spicy food.

짬뽕 (jjampong) is another noodle dish and a stable of Korean Chinese food. There appears to be some dispute on its origins; some say it may be based 炒码面 (chaomamian) but others say it may be another adaptation of a Japanese Chinese cuisine.

based on what I have been able to find, chaomamian broth is made with pork and bones and is clear. Jjampong uses fried seafood, vegetables, chili oil and chili paste/powder. Koreans think of this as a very typical Chinese food but there is no like-for-like dish in China it seems

잡채밥 (japchae bap/rice is another staple at Korean Chinese restaurants but...I am actually not sure why. It's basically glass noodles stir-fried with vegetables and other ingredients and put on top of rice. Japchae is a common side dish at Korean food restaurants.

I'll come back to this thread periodically when I can think of some other examples. Happy to take suggestions, any comments on origins of certain dishes or corrections to anything I incorrectly stated.