Kim’s article says she knows the name of the informant (last paragraph). The paragraph right before that says, “This suggest the source may be overseas”.
It would seem odd that Kim would even write that paragraph about the informant being overseas if she knows the name of the informant and he isn’t overseas.
Trying to analyze her article and assuming she really knows the name of the informant, I’d say he is a US citizen living abroad and had some interactions with the Trump campaign. It could be someone not currently on our “radar”.
Guessing it isn’t Page or Sessions.
“This suggest the source may be overseas”
Stefan Halper, Director of American Studies at the Department of Politics, University of Cambridge. Son-in-Law of CIA careerist Ray S. Cline.
Info here from Sundance is quite interesting. He suggests the mystery man is Stephan Halper. He is a Brit but has a house in Virginia.Lots of links in the article that are worth a read.