I am not fully certain but based on the caffe file names, I think it may be a variant of what is in this paper, https://arxiv.org/pdf/1805.03363.pdf https://ar

I am not fully certain but based on the caffe file names, I think it may be a variant of what is in this paper, https://arxiv.org/pdf/1805.03363.pdf https://arxiv.org/pdf/1805.03363.pdf which itself looks like a variant of MTCNN generally.