Chrome clearly outcompeted Firefox despite Firefox’ faster XSLT implematation, so perhaps the performance of a feature which is almost never used is not that significant either way?
Chrome is outcompeting (or cripling) Firefox - in taking control from the user, payed by the user - right now, with your comment all backward (and catch 22, cross-browser functionality bugs never to be fixed).
All downvoted ? If not performance of [ONE] feature like JS engine, what would make Chrome better ? (crippling others). JS is used so much only because all other options are kept broken (since Microsoft JS XMLHttpRequest - for applications not documents, being the lowest common denominator - against few bugs that needed to be fixed, not much changed) - otherwise there will be no need of JS for documents processing and less energy wasted - and the bill is payed not by corporations but by users, with extra tracking taxes.
Chrome mostly can do anything Firefox can do since removing its "legacy extensions", so Firefox has to remove XSLT too - as Google can't afford it being not helpful for tracking - and can compete only with its JS engine - so XSLT, if to stay, could in the future only be reimplemented in JS polyfills no more, making it less useful, not cached, not transparent - to let Chrome 'outcompete' others again, race to the bottom, everything looks like a nail.
Hopefully that could be enough to complete the evidence to split Google into pieces in antitrust case - or realizing that will make Google to back off ?
yet making it to be interlinked code too.. may not last, as codes like changing and finding new ways.
Fancy stuff as JS may be very useful and I like it too, momentary, when well applied, but it needs: an effort to use it, keep working, adapting, if interoperating, all specific, for the purpose - and power, can't open 1000s tabs. Different kind of being. More fun, like with the hammer for everyhthing - not shy like XSLT trying be transparent.