That's not what it's for, that's solved by showing the link when it's focused.
My guess is there was a desire to make Find-in-page automatically expand <details> elements and someone realized they could make it also work for custom disclosure widgets by giving the boolean attribute `hidden` an optional value.
My guess is there was a desire to make Find-in-page automatically expand <details> elements and someone realized they could make it also work for custom disclosure widgets by giving the boolean attribute `hidden` an optional value.