In the case of CSSFontFaceValue objects, shouldn't the have a member that stores the source as well?

For eg in the case:

@font-face {
font-family: "XYZ";
src: url("https://mdn.mozillademos.org/files/2468/VeraSeBd.ttf");
}

I am assuming the specified member fontFaceName stores the string "XYZ" and we will need to store the source in another member.Potentially in a CSSFontFaceSrcValue which inherits from CSSFontFaceValue? This can deal with the case where it is specified as a url or as a local value