Are you referring to the minimum and maximum values of the sliders ?
If so, for numeric values, the min and max values of the slider are the min and max values of the dataset, and the default value is the median of the dataset. But if your dataset is very large, only a fraction of it will be considered when looking for the min, max, and median values.
Also, note you can set a value that's outside the range if you click on the small "edit" button next to the slider.
