I'm on MacOS and typically use Safari as my main browser. I have several other browsers installed on my computer which I use for different things or just to try out from time to time. Orion is one I haven't tried in a while.

I've launched Orion and found that when I previously used it I saved some tabs - one of them being Ebay. I am not signed into my Ebay account in Orion but when I open this tab I'm seeing "Your Recently Viewed Items" and it's very much showing me the items I viewed in Safari just moments earlier.

Orion promotes itself as a privacy focused web browser.

Privacy by design, like no other browser.
Orion has been engineered from ground up as a truly privacy-respecting browser. We did it by embracing a simple principle - Orion is a zero telemetry browser. Your private information will never leave Orion by default.
And to protect your privacy on the web, Orion comes with industry-leading anti-tracking technology as well as a powerful built-in ad-blocker.

How does one browser know what the other browser is doing regardless if I'm, signed into my account on a particular website?