Version 4.0.3 is available upstream. Please consider updating! It seems that version 4.0.3 is available upstream, while the latest version in the Gentoo tree is 3.1.1-r1. You think this warning is false? Read more about it here.
Kissat is a "keep it simple and clean bare metal SAT solver" written in C.
It is a port of CaDiCaL back to C with improved data structures, better
scheduling of inprocessing and optimized algorithms and implementation.
Coincidentally "kissat" also means "cats" in Finnish.