Trainer "Not Listed"

So I just got my invite and have been playing around with a bunch of the settings in the Zwift sensor connect page. When I don’t connect my power meter, it comes up with a popup asking the type of trainer I have (for zPower no doubt).

I’m just wondering what the “Not Listed” trainer would mean? Is there a generalized power curve assigned to this or something? I tried it out with my rollers and it seems to give consistent with possibly slightly low power details.

I’d also like to know what “Not Listed” means? What does it provide?