Choosing UNDO after closing a tab reveals the (empty) non-private tabs page
Tested on Tor Browser 10.0.18 (89.1.1-Release).
Steps to reproduce
Open Tor Browser for Android
Navigate to any website
Close the tab by tapping the tabs icon and then the X next to the tab
Tap UNDO on the toast notification that appears near the bottom which says "Private tab closed UNDO"
Expected behavior Tab is restored, no change view from the private tabs screen.
Observed behavior Tab is restored, but the view is changed to the non-private tabs screen (which is empty, because there are only private tabs open).
The empty page might make the user might think that all their tabs are lost or that the tab failed to restore.