http://34reqsy6tqou6avwrkm23s4mpkrwz3drtq2e5yr7sywi76h7plnaahad.onion/articles/browsers.xhtml
Privacy-wise, it's still doing this crap (archive) (MozArchive) : When you install Vivaldi browser (“Vivaldi”), each installation profile is assigned a unique user ID that is stored on your computer. Vivaldi will send a message using HTTPS directly to our servers located in Iceland every 24 hours containing this ID, version, cpu architecture, screen resolution and time since last message.