No, for their "Jaldi" font they simply use:

    font-family: "Jaldi script=latin rev=2"

However, they are replacing what they think is a missing glyph with an image. For example, if I type the letter "r" while keeping the DOM inspector open, I see the text node containing the letter for a moment before it is replaced with an image element:

    <img class="content-editable-missing" data-missing-character="r" src="data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==">

This is most likely a javascript bug doing a false negative failed progressive enhancement.