With this box and whisker pot, the number of red dots represent what? qty of outliers?The left is a box and whisker plot of the right graph distribution.
Each red dot represent 1 data point.
Since, it's build using Graph Builder, you can turn on the graph builder control panel to check out the settings (i.e whether your box & whisker plot used outlier plot or quantile plot).
If quantile plot, you would see the lines in the box & whisker plot are similar to the quantile summary in distribution platform