It's not like the browsers can just switch to some better maintained XSLT library. There aren't any. There are about 1.5 closed-source XSLT 3 implementations, Altova and Saxonica. I don't want to sound ageist, but the latter is developed by the XSLT spec's main author, who is nearing retirement age. This library is developed behind closed doors, and from time to time zip files with code get uploaded to GitHub. Make of that what you will in terms of the XSLT community. For all of its elegance, XSLT doesn't seem very relevant if nobody is implementing it. I'm all for the open web, but XSLT should just be left in peace to slide into the good night.