Chrome is in a perpetual interface test. Every few weeks, we discover a new flag that turns things around like putting the URL bar at the bottom or eschewing the large tab cards for a smaller grid tab switcher. Google seems ready to settle on the latter as the latest Chrome Dev and Canary use this as the default layout but with a busier look that mashes elements from the new tab page into the tab switcher, with lots of icons, bars, and toggles.
This new tab switcher is a big departure from existing ones. The currently open tabs are moved down a few rows. A Google logo goes on top of the page with an incognito toggle right next to it. Below that is a search bar with a microphone, then you'll find the shortcuts to the sites you frequently visit.
Opening a new tab doesn't result in a new interface: You still get the same logo, search bar, and site shortcuts, with articles below those. So this new switcher may be handy but it's quite redundant.
Left: Old grid tab switcher. Middle: New tab switcher. Right: New with Duet.
I couldn't find any specific flag to trigger this UI. It seems to be the default when you reset all flags in Chrome Dev or Canary to default and restart the browser. I also tried a fresh install of these Chrome releases and got the horizontal tab switcher with the large cards, but when I enabled the grid layout (chrome://flags/#enable-tab-grid-layout) I got the new layout. Switching that flag to default and restarting Chrome (twice to be sure) didn't revert it. So I don't know what exactly triggers it, but it's there.
The new switcher works with both regular Chrome UI and Chrome Duet (bottom nav). If you want to give it a try, grab the Dev or Canary release of the browser and see if you get it by default. If not, you may need to turn on the grid flag.
Thanks: Louis Bohn