What is meant by "C-score is typically in the range of [-5,2] ?

C-score is typically in the range of [-5,2], where a C-score of higher value signifies a model with a high confidence and vice-versa.
I only get one model result and my C-score =1.61

However, What is meant by "C-score is typically in the range of [-5,2] ? Can you explain more details?

Thank you very much =)