1. htmlbuttonelement api: popovertargetaction

2. htmlbuttonelement api: popovertargetelement

3. htmlbuttonelement api: popovertargetelement: implicit anchor reference via `popovertargetelement`

4. htmlelement api: `beforetoggle` event: `beforetoggle` event fires at popover elements

5. htmlelement api: hidepopover

6. htmlelement api: popover

7. htmlelement api: popover: `hint` value

8. htmlelement api: showpopover

9. htmlelement api: showpopover: `source` option

10. htmlelement api: showpopover: `source` option: implicit anchor reference via `source`

11. htmlelement api: togglepopover

12. htmlelement api: togglepopover: returns `true` or `false`

13. htmlelement api: togglepopover: `source` option

14. htmlelement api: togglepopover: `source` option: implicit anchor reference via `source`

15. htmlelement api: `toggle` event: `toggle` event fires at popover elements

16. htmlinputelement api: popovertargetaction

17. htmlinputelement api: popovertargetelement

18. htmlinputelement api: popovertargetelement: implicit anchor reference via `popovertargetelement`

19. css selector: `::backdrop`: support on popovers

20. css selector: `:popover-open`

21. html element: button: popovertarget

22. html element: button: popovertargetaction

23. html element: button: popovertarget: implicit anchor reference via `popovertarget`

24. html element: input: popovertarget

25. html element: input: popovertargetaction

26. html element: input: popovertarget: implicit anchor reference via `popovertarget`

27. html attribute: popover

28. html attribute: popover: `hint` value