Some extra broken code in css chunks (head webpack variable / css custom property)?

[dartess]

I got some broken css code after build, like this:

head{--webpack--1378:root:fd1b8cae78bf93682b/fullWidthConteģ:cdĊ53f422185/disabled:a355bec39da88712059a/iĤmIcĢħd8aa4ąffc40086į8e/actiĢŖŘb6 ...

It looks like it's broken - it's not a valid CSS variable and it's not showing up in DevTools.

This started after upgrading to version 1.0.0.

What is this code? What is it for? Is there a way to disable it? I get a bunch of warnings from lightningccss, but they are not true. It seems to be related to this broken code, but I can't be sure because I can't disable it.