KLLR (Kernel Localized Linear Regression) generates estimates of conditional statistics in terms of the local slope, normalization, and covariance. This method provides a more nuanced description of population statistics appropriate for very large samples with non-linear trends. The code uses a bootstrap re-sampling technique to estimate the uncertainties and also provides tools to seamlessly generate visualizations of the model parameters.
https://ui.adsabs.harvard.edu/abs/2018MNRAS.478.2618F , https://ui.adsabs.harvard.edu/abs/2020MNRAS.495..686A