I'm very excited to see this, specifically the Scrollspy refactor [0]. During COVID lockdown, without anything better to do, I went down a rabbit hole debugging some wonky scroll behavior. A bunch of other people had encountered the same issue over the years, but it never was a top priority.<p>I did some research and discovered the Intersection Observer API, which seemed like a perfect fit for this use case. I hacked up a basic implementation[1], asked for some feedback, and promptly forgot about it. I was super stoked to see someone else pick up the idea and run with it, doing a much better job than I could have. Open source is fun!<p>[0] <a href="https://github.com/twbs/bootstrap/pull/33421" rel="nofollow">https://github.com/twbs/bootstrap/pull/33421</a><p>[1] <a href="https://github.com/twbs/bootstrap/pull/33015" rel="nofollow">https://github.com/twbs/bootstrap/pull/33015</a>