I have downloaded the DLC. I assume this is just a list of the ones where it isn't clear who they belong to, and The Brood entrance is listed as such. TBH, I've not looked as I haven't created them as a trio. However, I was annoyed that you can't use the Brood/Gangrel entrance for a tag team, only a trio.
I'm not climbing to the top of the mountain. I am the damn mountain!