It was intended as a META tag for subject type, to distinguish it as being about the functioning of the LIST (probably not the best choice) instead of an actual topic.
As in "list of comments"? I don't think people use that phrase very often.
Also, I think it's too specific and META would have been better.
What's up with that?
In a discussion thread, I can karma vote on anyone.
But if I select a person to see all their posts, for some people, karma is disabled while looking at them, and for others, it's not disabled. Same thing if I look at their posts under the list of all my posts.