This can be done by some experiments.
First: There are many automatic options of Mathematica.
In Mathematica 11.3 we can get more informations about functions, for example we can do
Options[fe] to find out more details.
Let's make things easier.
So we reconstruct a method named "NumericVector" in 1-Dimension[FeatureSpace] data maybe without the effect of DimensionReduction. In high-dimension data maybe done Standardize+PCA[Linear DimensionReduce] by Mathematica.
In your example, A and B are treated as Nominal Feature.
Let's concentrate on the numeric part.