TypoScript:includeCSSLibs is not parsed

[xerc]

.. is that on purpose?

[svewap]

No, just not implemented. I didn't see the need for it before.

[xerc]

might found a use-case to have two files @ https://web.dev/defer-non-critical-css/#optimize
includeCSSLibs; mandatory styles for FCP (in my case only one main.scss with Autoprefixer)
includeCSS; styles for element later in the page which will be loaded via the fake defer trick

search = /(<link) rel="(stylesheet)".+?(href="[^"]+") media="async">/
replace = $1 rel="preload" as="style" onload="this.onload=null;this.rel='$2'" $3><noscript>$1 rel="$1" $2></noscript>