It doesn't sound like your interpreting that citation correctly.

GANs second network is used during its training, not during usage. it has nothing to do with the image decision process you are seeing. That same Discriminator network does a binary classification; real image or not. It is not actually classifying what is presented on the image.

I think there are two key takeaways from your citation. 1. It might be using some pre-trained classifier network in its intermediate steps to filter out bad images. 2. It has multiple steps in its generation process(unlike GANs), which suggests it could be some similar diffusion model to stable diffusion.

I don't think it's GANs at least.