As part of the highlight pseudo-elements I think it might be helpful to introduce an empty pseudo-element that was located at the point of a mouse click or area of a finger tap, e.g. ::hit. This would enable authors to add visual clues for when and where a pointer interaction has happened, which is especially helpful in presentations for other spectators, although some users also employ it as an accessibility hint for themselves. Unlike OS or app features, a CSS-native solution could interact with other Selectors, so a click on a button or link could be styled differently than one on a paragraph, for instance.

I believe it has been proposed, but not added yet to css-anchor, to make the mouse pointer position a predefined and dynamic anchor reference. Combined with :active, this might look like a possible alternative, but it would involve another element box, whereas a designated pseudo-element could be styled directly. On the other hand, ::hit could solve this if it could be an anchor element.