Rearranging

Yes, and it changes the real order in Chrome.

Drag a card and drop it where you want it. The other cards move aside to show you where it will land. Drag a group by its name to move the whole group.

You can drag a tab from one window into another — it moves to that window for real.

This works in View by window, which shows your tabs as they're actually arranged. In View all, tabs are sorted by name, so there's no order to change.