Creating Web Widgets Using the Document Picture-in-Picture API
The general idea is that we create a Document Picture-in-Picture window (DPIP window), and then we put HTML, CSS, and JavaScript into it.
An all-too-early look at CSS Navigation Matching. Looks like a nice way to abstract view transitions directly in CSS... though still tough to grok at this early stage.
So, you got the ol' "Blocked aria-hidden" console warning. No error, no worry, right? Think again. And it's tougher to solve than most of the suggested fixes.