@Ryan R in the xschem_sky130 tests there is a sky130_tests/test_comparator.sch schematic which does a mismatch simulation, so each run has statistical variation on each transistor. It used to work, however tested today no variation is shown. This is probably a regression. I have asked to Tim Edwards. https://skywater-pdk.slack.com/archives/C016UL7AQ73/p1658056242392849