mlr3 - 关于 dalex 包的一点困惑

Question

你好 mlr3 团队。

我对 mlr3 书中提供的 dalex 包有疑问。具体来说，这里

ranger_exp <- explain_mlr3(fifa_ranger,
        data     = fifa,
        y        = fifa$value_eur,
        label    = "Ranger RF",
        colorize = FALSE)

(a) 'fifa' here is a training data or full data which also include test sets?

(b) I read somewhere that it should not include the class variable but here it appears to include? 

(c) For the instance level explanation, like fifa["Cristiano Ronaldo",], which feature/column of the observation/row need to be included here, if we do not have a unique column (like iD or name) in our dataset? 

先感谢您