I'm checking my caching headers for assets served by file server. It all works as expected, but RedBot claims it should be adding Vary when serving 206, 304.

I've checked Caddy site itself that it's not some misconfiguration on my end, but it doesn't seem to be, the case there seems even worse:
https://redbot.org/?uri=https://caddyserver.com/resources/css/docs.css?v=dfd5278

It seems the Vary needs to be sent in both cases.