It is in fact part of the latest standard: https://html.spec.whatwg.org/multipage/popover.html#the-popover-attribute https://html.spec.whatwg.org/multipage/popo

It is in fact part of the latest standard: https://html.spec.whatwg.org/multipage/popover.html#the-popover-attribute https://html.spec.whatwg.org/multipage/popover.html#the-popo... Safari and Edge preview builds are supporting popover as well. Mozilla has indicated they’re “positive” on it. Still might be a long time before it’s generally usable but it is in the standard.