Super_Affection said:
I agree it's not a tail, but I don't believe it's a perspective error or part of the background either. Whatever those are, they are part of the character, as seen in reference sheet post #7004519 and other posts of the character. It's just that they emerge from her neck rather than lower back like a tail.
Oops, I was watching to the cable in the character's back, and not those blue cable-like things in the neck. That being said, I couldn't find any specific tag for that. However, the Wiki specifies the cable tag can be used for science fiction related equipment and machinery, thus meaning that single tag applies for those things in the character's neck, since it looks like some kind of cyborg.