The very first plot shown in the article was generated with custom scripts, published here (https://github.com/csun/simple_gnucash_budget_plots)

I'm not sure how much it's changed since 2014. I think the "budgeting" system is still probably as bad as it was back then, though (and by bad I mean not really applicable for personal use, probably good for businesses). That's why I wrote this budget plotting script.