Comment by immibis

As much as I think XSLT is cool, if it's used by practically nobody and contains real security vulnerabilities... oh well. You can't deny that combination is a good objective reason to remove it.

And browsers are too big with too many features; reducing the scope of what a browser does is good (but not enough by itself to remove a feature).

Maybe one day it will come back as a black-box module running in an appropriate sandbox - like I think Firefox uses for PDF rendering.