So RSS won't be supported anymore and other formats too.

Only the web HTML + CSS + JS will remain and Chrome is pushing implementations at a faster pace that the other browsers can not . There is effectively an attempt to capture the web by Google.

I remember the library for XLST used in browsers is not maintained by the big corporations. Ah it's LibXML.

The depreciation notice: https://groups.google.com/a/chromium.org/g/blink-dev/c/CxL4gYZeSJA/m/yNs4EsD5AQAJ

Ah yes, a maintainability thing "Chromium uses the libxslt library to process these transformations, and libxslt was unmaintained for ~6 months of 2025".

Usage of the JS XSLTProcessor API is fairly volatile, registering somewhere between 0.01% and 0.1% of page loads, averaging around 0.05% over time. These numbers are above the typical 0.001% deprecation threshold. Again, we feel that the increased potential for breakage is balanced by the reduced security risk to 100% of Chromium users.

It's for security reason? XSLT users hacked are 0. Where are the security vulnerability?

The unpaid work of volunteers for core libraries is unsustainable. We can all agree on that.

There is few comments suggesting sustainable models.