Crafted optimization instances in OPB format, inspired by (Elffers et al. 2018; Vinyals et al. 2018), but generated with larger parameters so as to be more challenging, allowing to “stress-test” combinatorial solvers by exposing them to problems that provably require sophisticated reasoning. - Elffers, J.; Giráldez-Cru, J.; Nordström, J.; and Vinyals, M. 2018. Using Combinatorial Benchmarks to Probe the Reasoning Power of Pseudo-Boolean Solvers. - Vinyals, M.; Elffers, J.; Giráldez-Cru, J.; Gocht, S.; and Nordström, J. 2018. In Between Resolution and Cutting Planes: A Study of Proof Systems for Pseudo-Boolean SAT Solving.