Current state of TLS session resumption tracking

Dear HN, few years ago big news were around about TLS session (resumption) tracking.

I find no current information whether this issue has been fixed or if current browsers mitigate it in private mode; as it seems to basically be a feature I assume any sort of fix can only be in context of private mode (per tab in safari or per-container in firefox) or history-clearing?

Neither I can find a "test page".

Do we have any?

Thankyou