Where do I find the solver error code definitions for Coin-OR CBC that Pyomo returns?

Question

I see ERROR: - Solver (cbc) returned non-zero return code (-9) when running my Pyomo problem.

I have tried solve(instance, tee=True, keepfiles=True, logfile="my.log") but the my.log is not appearing. I have searched through the Pyomo and cbc github repositories but I do not understand how to trace the error codes.