I have another possible explanation for why the wild-type genes keep showing up: maybe they work better for feral chickens. If white chickens, or black chickens, or bigger chickens (etc) get eaten by predators, the only ones left to breed are the wild-type ones.
They can call a breed anything they want.
The name of the breed has nothing to do with whether the original wild jungle fowl or the original velociraptor is extinct.
I never heard of it before either, but now that I look, it is on the list of breeds recognized on the American Bantam Association website. Neat!
https://www.bantamclub.com/recognized-breed-and-variety
The American Bantam Association recognizes a breed called "Junglefowl" in a color called...