Evolution of the features and PCA performance for the target (DES16X3jj, possible Type II SN; i band). This object was captured by short exposures (10 s) and has low brightness. It generally has negative flux in our difference images. We thus only use six features, the same as in Figure 17. The corresponding light curve is shown in Figure 4. Here, feature Nos. 1, 4, and 5 are less effective than the others. The first point has low S/N, but the feature quantile Nos. 2 and 3 (and q _P) are still high.