foreignObject is not in the html namespace so you need to remove the xmlns="http://www.w3.org/1999/xhtml" from the foreignObject element and put it on the <h1> tag instead.html does not process xmlns attributes at all which is why it works on a html ...
I think Firefox is right per the SVG specification i.e.https://www.w3.org/TR/SVG/coords.html#VectorEffectsvector-effect defaults to viewport (and Firefox only supports viewport anyway, I suspect other viewers do to i.e. nobody supports screen)Per htt...
