How can I know some special points according to the 'probplot'

For example, I have a group of points in 2D plane.

Then, I make a probplot (normal) of them.

p = [xi, yi] i = 1, ..., N probplot(p);figure(gcf);

Then I found some points in the figure are far from the line. Can I know which points they are?

But I don't understand what the reference line is. For a 2d point set, I got a 2-line figure. Does it mean each line belongs to one dimension of the point's coordinates. I mean one line indicates x coordiante and another corresponds to y.