Microsoft has released a Windows 11 build for Windows Insiders on the beta channel which includes File Explorer tabs. KB5014770 takes the build to 22631.160 and for some Windows Insider it includes Tabs in File Explorer just like the Dev Channel released last week. Microsoft are A/B testing the feature so not all Windows Insiders will get the update.
File Explorer also has a refreshed layout with an updated navigation pane which includes OneDrive with the user account name and moved away from the PC drives.
Here is my video of Tabs in Windows 11 File Explorer: