The chrome around a figure
Controls live in the chart footer rather than the header, on the principle that a reader should meet the figure before they meet its switches.
SegmentedControl
One of a small fixed set. A keyboard-navigable radio group, not a row of buttons — arrow keys move within it, and only the selected option is in the tab order.
Switch
For settings that take effect immediately. If a control needs an apply step, it is a checkbox in a form, not this.
SizeControl
A Datawrapper-style preview: tap a mobile/tablet/desktop preset, type an exact width and height, or drag the handle in the figure's corner. What resizes is the whole figure — title, chart, source — because that's what an embed contains; a title holding its desktop measure while the plot narrows tells you nothing. The bar stays outside it, at full width.
Demo content — the fields live in the footer, next to the source line.