mathMLnode = function(label: string): mathMLTree.MathNode {
    const node = new mathMLTree.MathNode(
        "mo",
        [new mathMLTree.TextNode(stretchyCodePoint[label.replace(/^\\/, '')])],
    );
    node.setAttribute("stretchy", "true");
    return node;
}
This file provides support to buildMathML.js and buildHTML.js
for stretchy wide elements rendered from SVG files
and other CSS trickery.