godot/scene/theme/icons/option_button_arrow.svg

<svg xmlns="http://www.w3.org/2000/svg" width="12" height="12"><path fill="none" stroke="#b2b2b2" stroke-linecap="round" stroke-linejoin="round" stroke-opacity=".85" stroke-width="2" d="m2 4 4 4 4-4"/></svg>