> "Select multiple" is just a list of checkboxes.
Not necessarily. I've seen more than one production app with a custom filtering dropdown list of items with checkboxes.
I built a couple variants of that in React at my last gig for the company's design system. The keyboard nav was complex... that component is one of the work artifacts that I'm most proud of.
> custom filtering dropdown
I already said that. "Select" is not filterable in the browser already, so `select[multiple]` has no chance of seeing that in this decade.
However you slice/style it, it's just checkboxes (that you can filter/reorder)