Help:CSS_best_practices advices to use raw file URLs for images and font files used via CSS on many pages, rather than /wiki/Special:FilePath or /wiki/Special:Redirect/file.

It claims that in addition for the HTTP redirect overhead itself (double redirect in the case of Special:FilePath) these redirects prevent the browser caching of the file itself, which can of course be a significant harm to performance.

My testing in the browser devtools however indicate that the file itself is cached normally (see screenshot below).

The concern about the HTTP redirect still remains of course, however that's a smaller impact and there's a trade-off with convenience and maintainability.

Any thoughts? Am I missing something in my test? Thanks.