Responsive accordions are actually solved using CSS nowadays, but plenty of other things aren't, and the web has definitely needed an API or library like this for a long, long time. So it's great that we now have it.

Building something like this was certainly possible before, but it was a lot of effort. What's changed is simple: AI. It seems clear this library was mostly built in Cursor using an agent. That's not a criticism, it's a perfect use of AI to build something that we couldn't before.