Cloudflare R2 files are not cached when requested via custom domain

I connected a public R2 bucket through my domain. Now this domain has Proxied status, but all GET requests to files on this domain get to R2 and counted as Class B operations, although logically they should be distributed from the cache. Who can clarify how it should be?

How are the cache-control headers on the responses?

You might need to enable the caching on those resources.

I do not use any headers. How to enable caching?

You do, for sure, they will be set automatically, but I’m not sure how they are set by R2.

Either give me a link to some resource or post the response/request headers.