Standard Deviation of Classifier Models
Classifiers are commonly scored on the cross entropy or some other divergence, since we're talking about distributions. A multi-class classifier will give you a "score" associated with each class (option, outcome). It is usually easy to transform this score into a probability, so that the options add up to one. Furthermore, it is possible to associate with each class a confidence distribution. I don't know if this is what you are asking about, but here's a great blog post on it.