animateTransform

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
    <rect x="50" y="50" height="100" width="100" stroke="black" fill="yellow">
        <animateTransform
            attributeType="XML"
            attributeName="transform"
            type="rotate"
            begin="0s"
            dur="10s"
            from="0"
            to="360"
            repeatCount="indefinite"
        />
    </rect>
</svg>