I see that ::picker(select) That’s the trigger for everything. Taking a quick look at Una’s post, I see that there are more options to choose something different Parts including:
(the current selection)
(which now accepts HTML between tags!)
option::before
option:checked (a little confusion here with the selected option)
(the little chevron arrow marker thing)
So maybe Chrome is more of a fan of extending native with additional CSS functionality to select the existing parts instead of continuing with an entirely new element. This is cool because one of Una’s demos shows how we still get the default setting Behavior even if a browser does not support the new selectors.