To make the web safer, they will replace simple static web pages with remote code execution on the user's machine. Yet another “fuck you” to people who don't want to shove JavaScript in everything. God forbid I serve a simple static site to people. Nonono. XSLT is fantastic for people who actually want to write XML documents like the good old days, or add styling to Atom feeds.
Edit: and for a slightly calmer response: Google has like, a bajillion dollars. They could address any security issues with XSLT by putting a few guys on making a Rust port and have it out by next week. Then they could update it to support the modern version in two weeks if it being out of date is a concern. RSS feeds need XSLT to display properly, they are a cornerstone of the independent web, yet Google simply does not care.
Edit: and for a slightly calmer response: Google has like, a bajillion dollars. They could address any security issues with XSLT by putting a few guys on making a Rust port and have it out by next week. Then they could update it to support the modern version in two weeks if it being out of date is a concern. RSS feeds need XSLT to display properly, they are a cornerstone of the independent web, yet Google simply does not care.