bug 1404891 - https://bugzilla.mozilla.org/show_bug.cgi?id=1904891 will implement the screen option. That will give you pretty much the same results as Firefox's previous behaviour.vector-effect: non-scaling-stroke screen;
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...