In 2015, the lead developer for seaborn replied to a feature request asking for access to the statistical values used to generate plots by saying, "It is not available, and it will not be made available."
So, unfortunately, this feature does not exist in seaborn, and seems unlikely to exist in the future.
Update: in March 2018, seaborn's lead developer reiterated his opposition to this feature. He seems... uninterested in further discussion.
