Greasy Fork

What does this script do exactly?

What is this a heatmap of and what does it look like? A screenshot would be handy, if possible.

Thanks :)

Hey, have a look at this thread on the Wanikani forums https://community.wanikani.com/t/userscript-wanikani-heatmap/34947

There's also this thread where people share screenshots of their own heatmaps https://community.wanikani.com/t/heat-map-stories-wanikani-activity-chart/34965