Do you mean charts? If so, it's Datawrapper: https://www.datawrapper.de/charts

One of the quite expensive paid plans, as the free one has to have "Created with Datawrapper" attribution at the bottom. I would guess they've vibe-coded their way to a premium version without paying, as the alternative is definitely outside individual people's budgets (>$500/month).

Inspecting the page, I can see some classes "dw-chart" so I looked it up and got to this: https://www.datawrapper.de/charts. Looks a bit different on the page, but I think that's it.

it is indeed Datawrapper like other posters have said. It works well for interactivity on a static blog like Hugo.