The issue in the HTML Standard says this would replace "default fetch and process the linked resource", but I'm not sure how good that is given how much common infrastructure it covers, such as referrer policy and integrity.

Yes, these days I'd kind of prefer to invert the model. Especially after @domfarolino's work revamping link fetching to be more hookable, I think more likely we could define "linked resource fetch setup steps" for stylesheets, and keep it all centralized in HTML.

I noticed that the CSSOM variant does not check for the response's status to be 2xx.

Yes, these days I'd kind of prefer to invert the model. Especially after @domfarolino's work revamping link fetching to be more hookable, I think more likely we could define "linked resource fetch setup steps" for stylesheets, and keep it all centralized in HTML.

I tend to agree. To make the CSS variant variable it would need to copy or import things from HTML such as "potentail-CORS" stuff which should have knowledge about crossorigin attributes of link elements - an HTML concern rather than CSS.