cgsecurity.org

The program says one must reboot to see the changes.

Well certainly sometimes replugging in the USB disk would be enough.

Or maybe just remounting it.

So perhaps the message should say 'may' and not 'must'.

Else some users might reboot unnecessarily.

I want to delete, not undelete. Alas, all I can choose is:

Use Left arrow to go back, Right to change directory, h to hide Alternate Data Stream
q to quit, : to select the current file, a to select all files
C to copy the selected files, c to copy the current file

No, I cannot delete the normal ...

On https://www.cgsecurity.org/wiki/TestDisk_Download
please be sure to mention e.g.,

2.1.4 Debian
TestDisk is available for Debian.
As root,
apt update
apt install testdisk

So we find out *before* we download!