godot/scene/theme/icons/checked.svg

<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16"><rect width="14" height="14" x="1" y="1" fill="#fff" fill-opacity=".75" rx="2.333"/><path fill="#1a1a1a" d="m11.5 3.75-5.6 5.6-1.7-1.7-1.5 1.5 3.2 3.2 7.1-7.1z"/></svg>