ngspice
Corner definitions for ngspice.
A simulation is run as a set of orthogonal corners: process (K...), temperature (T...), supply (V...) and a general corner (Gt). cicsim is told which combinations to run, for example
cicsim run --name Sch_etc tran Sch Gt "Kss,Kff,Ksf,Kfs" "Th,Tl" "Vl,Vh"
and each name resolves to a .lib in one of the files here.
temperature.spi and supply.spi are written by hand. corners.spi is generated from the corner dictionary in cicsim/cicsim.yaml by make corners, so the process corners never drift between the two.