lib/plugins/tag/iframe.js
function iframeTag(args, content) {
  const url = args[0];
  const width = args[1] && args[1] !== 'default' ? args[1] : '100%';
  const height = args[2] && args[2] !== 'default' ? args[2] : '300';

  return `<iframe src="${url}" width="${width}" height="${height}" frameborder="0" allowfullscreen></iframe>`;
}
function iframeTag(args, content) {
  const url = args[0];
  const width = args[1] && args[1] !== 'default' ? args[1] : '100%';
  const height = args[2] && args[2] !== 'default' ? args[2] : '300';

  return `<iframe src="${url}" width="${width}" height="${height}" frameborder="0" allowfullscreen></iframe>`;
}
Iframe tag

Syntax:
{% iframe url [width] [height] %}