Isn’t popover kinda useless without a position api of the popover element? Most of the time you want to create a ‚better‘ title. But the hard part is not something like the popover it‘s the positioning (can’t do middle at the end of screen even if the others are middle since it would cut stuff or add temporary scrollbars usw.?)
There are web standards and then there are web standards.
There are some that Chrome just scribbles on a napkin, throws them into standards committees, and immediately releases even if the napkin cannot even be read by anyone. Because this benefits one or other group inside Google. See basically all hardware APIs.
With others Chrome sometimes just barges ahead even if the final shape of the standard isn't fully agreed on. YOLO. The links above are quite telling. Many of those have the following disclaimer: "This feature is experimental. Use caution before using in production."
https://caniuse.com/mdn-html_elements_details_name
Invoker Commands
https://caniuse.com/mdn-html_elements_button_commandfor
Popover API
https://caniuse.com/mdn-api_htmlelement_popover
Popover=hint
https://caniuse.com/mdn-api_htmlelement_popover_hint