There are a few things in the documentation of plot_shift that is lacking:

• The X axis of the scatter plot is hard-coded to "score (a.u.)", but what that means is a mystery.
• The scatter plot has lines connecting the X and the Y deciles, with color which I can tell only by reading the source code.
• The Y axis of the plot of the shift function also has the "(a. u.)" with unknown meaning.
• It might be a good idea to have a sentence about or doc link to the matplotlib violinplot, for those who don't know about it before.

It is also not immediately clear from the examples in the documentation what is the effect of the "show_median" option, perhaps because a percentile line is right on top of it.