How to download a chart with FitNesse for Appian?

The page I am testing has a line chart with a download icon on it with the tooltip Download PNG Image, but I am unsure how to have my FitNesse script perform the download. I see support for downloading charts was added to FitNesse for Appian November 2023 - Release 23.4, but I don't see in the Cheat Sheet or documentation how to download charts.