Chrome developer blog article about this:

https://developer.chrome.com/blog/tether-elements-to-each-other-with-css-anchor-positioning/

As mentioned in #6631, it's now called the Popover API

• https://open-ui.org/components/popover.research.explainer/
• https://developer.chrome.com/docs/web-platform/popover-api/

The Popover API is planned for launch in Chrome 110, available in stable in early February 2023 (check the Chrome Roadmap for updates).

I2S by Chrome: https://groups.google.com/a/chromium.org/g/blink-dev/c/uB_jxbRmjAM/m/Ona8hJ1BAQAJ

Support for popover and popover=auto has been enabled in Safari TP 166:

• WebKit/WebKit@6a08cd6
• WebKit/WebKit@725f643

Chrome support is still in origin trial phase, with shipping pushed to Chrome 114 https://chromestatus.com/feature/5463833265045504

Chrome developer blog article about this:

https://developer.chrome.com/blog/tether-elements-to-each-other-with-css-anchor-positioning/

@ThreeDfish The Anchor API does not appear to be part of the popover API, though the two naturally would go extremely well together. Indeed each would feel incomplete without the other. I created a separate issue for the Anchor API.

Edit: CSS anchor positioning has already been added. Unfortunately it has zero support.
https://caniuse.com/css-anchor-positioning

Hi! I'm not this this is what you're asking for, if not you can ignore my intervention.
From Hat I see popover attribute and APIs are currently present on CanIUse? Am I missing something?

https://caniuse.com/?search=popover

@TixieSalander
e.g. :popup-open