[progval]

> The browsers don't share third-party caches across domains

Do you have a source for this? I believe(d?) it too, but when re-checking just now, I could not find any.

[isbvhodnvemrwvn]

I couldn't find anything related to Edge.

Safari: https://webkit.org/blog/8613/intelligent-tracking-prevention...

Chrome: https://developers.google.com/web/updates/2020/10/http-cache...

Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1536058

[progval]

Great, thanks!