When the specified value is outside the range [0,1], Blink and Safari are currently not clamping the computed value of fill-opacity, flood-opacity, stop-opacity, stroke-opacity. Edge and Firefox (and spec) are clamping the computed value to [0,1] https://svgwg.org/svg2-draft/painting.html#FillOpacity https://svgwg.org/svg2-draft/painting.html#StrokeOpacity https://drafts.fxtf.org/filter-effects/#FloodOpacityProperty Computed value: the specified value converted to a number, clamped to the range [0,1] https://svgwg.org/svg2-draft/single-page.html#pservers-StopOpacityProperty Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) must be clamped to this range. Blink bug: https://bugs.chromium.org/p/chromium/issues/detail?id=908058 All browsers are clamping the computed value of opacity and shape-image-threshold. http://jsfiddle.net/ericwilligers/zmgy8735/ (Blink and Safari and Firefox have different behavior when animating: https://github.com/w3c/csswg-drafts/issues/3340 )
Blink (like Edge and Firefox) now clamps the computed value of *-opacity https://wpt.fyi/results/svg/painting/parsing/stroke-opacity-computed.svg
<rdar://problem/47449828>
Based on attached "JSFiddle" in Comment 01, Safari 15.5 only differs on shape-image-threshold from other browsers (Chrome Canary 105 and Firefox Nightly 103). For all other tests, it is now consistent with other browsers. I think separate bug can be raised for "shape-image-threshold" issue but I will leave it up to others to decide. Thanks!
Blink Commit - https://chromium.googlesource.com/chromium/src.git/+/7357da2a70de65bf267e8da97dc31e5e96baee20
closing this and raising new for 'shape-image-threshold'. Look into 'See Also'.