Given that XSLT transforms XML into HTML, why has no one simply built a server side XSLT system? So these existing sites that use XSLT can just adopt that, and not need to rely on browser support.
I remember Gentoo Linux had all its official documentation in a system just like that, maybe 15-20 years ago. It was written and stored as XML, XSLT-processed and rendered into HTML on the webservers.
I want to use it on an RSS feed: to make it sensible when a new users clicks on an RSS link.
I specifically want it to be served as XML so it can still be an RSS feed: I don't even need the HTML to look that great: I have the actually website for that.
Server-side XSLT tools have existed for 25 years or so. The people complaining about this want existing websites using XSLT on the client to continue to work without changes.
It's actually possible to support it by re-implement it by js or compile to wasm and running on client side. There are extensions to support pdf(pdf.js), flash(Ruffle), mht(UnMHT). So it should be possible to do the same thing for XSLT. The real question is "Who want to"? Does xslt have a large user base like pdf, flash, mht?