Normalized confusion matrix of mock catalogs for test samples. Each row of this matrix represents a test sample taken from a certain cosmology (containing 700 galaxy clusters), where each cell represents the fraction of galaxy clusters classified as belonging to the x-label cosmology. The diagonal of the matrix represents the recall rate (i.e., the fraction of clusters correctly classified) coinciding with the median recall of each violin in Fig. 5. The non-diagonal elements of the matrix represent the fraction of clusters that have been misclassified to other universes. As it can be seen from Fig. 5 and this figure, ML has a low recall rate and large misclassified fractions for the central models (such as M5, M6, M7, and M9), indicating that these cosmologies have more overlap with neighboring cosmologies.