SVG 2 has no details on how the script element is processed.

document.currentScript may return an SVGScriptElement, but we don't define how that is set.
See whatwg/html#913

Need to do some analysis to determine what else is missing.
Ideally we would defer as much as possible to the HTML spec. I think this is intended by the statement currently in the SVG spec that says:

A ‘script’ element is equivalent to the ‘script’ element in HTML

But that's not enough.